TCSH(1)                                                   TCSH(1)

NAME
       tcsh  - C shell with file name completion and command line
       editing

SYNOPSIS
       tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
       tcsh -l

DESCRIPTION
       tcsh is an enhanced but completely compatible  version  of
       the  Berkeley  UNIX C shell, csh(1).  It is a command lan-
       guage interpreter usable  both  as  an  interactive  login
       shell and a shell script command processor.  It includes a
       command-line editor (see The  command-line  editor),  pro-
       grammable  word  completion  (see Completion and listing),
       spelling correction (see Spelling correction),  a  history
       mechanism  (see  History  substitution),  job control (see
       Jobs) and a  C-like  syntax.   The  NEW  FEATURES  section
       describes   major   enhancements   of  tcsh  over  csh(1).
       Throughout this manual, features of tcsh not found in most
       csh(1)  implementations (specifically, the 4.4BSD csh) are
       labeled with `(+)', and  features  which  are  present  in
       csh(1)  but not usually documented are labeled with `(u)'.

   Argument list processing
       If the first argument (argument 0) to  the  shell  is  `-'
       then it is a login shell.  A login shell can be also spec-
       ified by invoking the shell with the -l flag as  the  only
       argument.

       The rest of the flag arguments are interpreted as follows:

       -b  Forces a ``break'' from option processing, causing any
           further  shell  arguments  to be treated as non-option
           arguments.  The remaining arguments will not be inter-
           preted  as  shell  options.   This may be used to pass
           options to a shell script without confusion or  possi-
           ble  subterfuge.  The shell will not run a set-user ID
           script without this option.

       -c  Commands are read from the following  argument  (which
           must  be  present,  and  must  be  a single argument),
           stored in the command shell  variable  for  reference,
           and  executed.   Any remaining arguments are placed in
           the argv shell variable.

       -d  The shell loads the directory stack from ~/.cshdirs as
           described  under  Startup and shutdown, whether or not
           it is a login shell. (+)

       -Dname[=value]
           Sets  the  environment   variable   name   to   value.
           (Domain/OS only) (+)

       -e  The  shell  exits  if  any  invoked command terminates
           abnormally or yields a non-zero exit status.

       -f  The shell ignores ~/.tcshrc, and thus starts faster.

       -F  The shell uses fork(2) instead of  vfork(2)  to  spawn
           processes. (Convex/OS only) (+)

       -i  The shell is interactive and prompts for its top-level
           input, even if  it  appears  to  not  be  a  terminal.
           Shells  are  interactive  without this option if their
           inputs and outputs are terminals.

       -l  The shell is a login shell. Only applicable if  -l  is
           the only flag specified.

       -m  The  shell  loads ~/.tcshrc even if it does not belong
           to the effective user. Newer  versions  of  su(1)  can
           pass -m to the shell. (+)

       -n  The  shell  parses commands but does not execute them.
           This aids in debugging shell scripts.

       -q  The shell accepts SIGQUIT (see  Signal  handling)  and
           behaves  when it is used under a debugger. Job control
           is disabled. (u)

       -s  Command input is taken from the standard input.

       -t  The shell reads and executes a single line  of  input.
           A  `\' may be used to escape the newline at the end of
           this line and continue onto another line.

       -v  Sets the verbose shell variable, so that command input
           is echoed after history substitution.

       -x  Sets  the  echo  shell  variable, so that commands are
           echoed immediately before execution.

       -V  Sets the verbose shell variable even before  executing
           ~/.tcshrc.

       -X  Is to -x as -V is to -v.

       After  processing  of  flag arguments, if arguments remain
       but none of the -c, -i, -s, or -t options were given,  the
       first argument is taken as the name of a file of commands,
       or ``script'', to be executed.  The shell opens this  file
       and  saves  its  name for possible resubstitution by `$0'.
       Since many systems use either the standard  version  6  or
       version  7  shells  whose shell scripts are not compatible
       with this shell, the shell uses such a `standard' shell to
       execute  a script whose first character is not a `#', i.e.
       which does not start with a comment.

       Remaining arguments are placed in the argv shell variable.

   Startup and shutdown
       A login shell begins by executing commands from the system
       files /etc/csh.cshrc and /etc/csh.login.  It then executes
       commands  from  files  in the user's home directory: first
       ~/.tcshrc (+) or, if ~/.tcshrc  is  not  found,  ~/.cshrc,
       then  ~/.history (or the value of the histfile shell vari-
       able), then ~/.login, and finally ~/.cshdirs (or the value
       of  the  dirsfile shell variable) (+).  The shell may read
       /etc/csh.login before instead of after /etc/csh.cshrc, and
       ~/.login before instead of after ~/.tcshrc or ~/.cshrc and
       ~/.history, if so compiled; see the  version  shell  vari-
       able. (+)

       Non-login shells read only /etc/csh.cshrc and ~/.tcshrc or
       ~/.cshrc on startup.

       Commands like stty(1) and tset(1), which need be run  only
       once  per login, usually go in one's ~/.login file.  Users
       who need to use the same set of files with both csh(1) and
       tcsh  can  have only a ~/.cshrc which checks for the exis-
       tence of the tcsh shell variable (q.v.) before using tcsh-
       specific  commands,  or  can  have  both  a ~/.cshrc and a
       ~/.tcshrc  which  sources  (see   the   builtin   command)
       ~/.cshrc.   The  rest  of  this manual uses `~/.tcshrc' to
       mean `~/.tcshrc or, if ~/.tcshrc is not found,  ~/.cshrc'.

       In the normal case, the shell begins reading commands from
       the terminal, prompting with `> '.  (Processing  of  argu-
       ments and the use of the shell to process files containing
       command scripts are described later.)  The  shell  repeat-
       edly  reads a line of command input, breaks it into words,
       places it on the command history list, parses it and  exe-
       cutes each command in the line.

       One  can log out by typing `^D' on an empty line, `logout'
       or `login' or via the shell's  autologout  mechanism  (see
       the autologout shell variable).  When a login shell termi-
       nates it sets the logout shell  variable  to  `normal'  or
       `automatic'  as  appropriate,  then executes commands from
       the files /etc/csh.logout and  ~/.logout.  The  shell  may
       drop  DTR  on logout if so compiled; see the version shell
       variable.

       The names of the system login and logout files  vary  from
       system  to  system for compatibility with different csh(1)
       variants; see FILES.

   Editing
       We first describe The command-line editor.  The Completion
       and  listing and Spelling correction sections describe two
       sets of functionality which are implemented as editor com-
       mands  but  which  deserve  their own treatment.  Finally,
       Editor commands lists and describes  the  editor  commands
       specific to the shell and their default bindings.

   The command-line editor (+)
       Command-line  input can be edited using key sequences much
       like those used in GNU Emacs  or  vi(1).   The  editor  is
       active  only when the edit shell variable is set, which it
       is by default in interactive shells.  The bindkey  builtin
       can  display  and  change  key  bindings.  Emacs-style key
       bindings are used by default (unless the  shell  was  com-
       piled  otherwise;  see  the  version  shell variable), but
       bindkey can change the key bindings to  vi-style  bindings
       en masse.

       The  shell  always binds the arrow keys (as defined in the
       TERMCAP environment variable) to

           down    down-history
           up      up-history
           left    backward-char
           right   forward-char

       unless doing so would alter another single-character bind-
       ing.   One  can  set the arrow key escape sequences to the
       empty string with settc to prevent  these  bindings.   The
       ANSI/VT100 sequences for arrow keys are always bound.

       Other  key bindings are, for the most part, what Emacs and
       vi(1) users would expect and can easily  be  displayed  by
       bindkey,  so there is no need to list them here. Likewise,
       bindkey can list the editor commands with a short descrip-
       tion of each.

       Note that editor commands do not have the same notion of a
       ``word'' as does the shell. The editor delimits words with
       any  non-alphanumeric characters not in the shell variable
       wordchars, while the shell recognizes only whitespace  and
       some of the characters with special meanings to it, listed
       under Lexical structure.

   Completion and listing (+)
       The shell is often able to complete  words  when  given  a
       unique abbreviation.  Type part of a word (for example `ls
       /usr/lost') and hit the tab key to run  the  complete-word
       editor   command.    The   shell  completes  the  filename
       `/usr/lost' to `/usr/lost+found/',  replacing  the  incom-
       plete  word  with  the  complete word in the input buffer.
       (Note the terminal `/'; completion adds a `/' to  the  end
       of  completed  directories and a space to the end of other
       completed words, to speed  typing  and  provide  a  visual
       indicator  of  successful completion.  The addsuffix shell
       variable can be unset to prevent this.)  If  no  match  is
       found  (perhaps `/usr/lost+found' doesn't exist), the ter-
       minal bell rings.  If the word is already  complete  (per-
       haps there is a `/usr/lost' on your system, or perhaps you
       were thinking too far ahead and typed the whole  thing)  a
       `/'  or  space  is  added  to  the end if it isn't already
       there.

       Completion works anywhere in the line,  not  just  at  the
       end;  completed  text  pushes  the rest of the line to the
       right. Completion in the middle of a word often results in
       leftover  characters to the right of the cursor which need
       to be deleted.

       Commands and variables can be completed in much  the  same
       way.  For example, typing `em[tab]' would complete `em' to
       `emacs' if emacs were the  only  command  on  your  system
       beginning with `em'.  Completion can find a command in any
       directory in path or if given  a  full  pathname.   Typing
       `echo  $ar[tab]'  would  complete  `$ar'  to `$argv' if no
       other variable began with `ar'.

       The shell parses the input buffer to determine whether the
       word  you  want to complete should be completed as a file-
       name, command or variable.  The first word in  the  buffer
       and  the first word following `;', `|', `|&', `&&' or `||'
       is considered to be a command.  A word beginning with  `$'
       is  considered to be a variable.  Anything else is a file-
       name. An empty line is `completed' as a filename.

       You can list the possible completions of  a  word  at  any
       time  by typing `^D' to run the delete-char-or-list-or-eof
       editor command.  The shell lists the possible  completions
       using the ls-F builtin (q.v.)  and reprints the prompt and
       unfinished command line, for example:

           > ls /usr/l[^D]
           lbin/       lib/        local/      lost+found/
           > ls /usr/l

       If the autolist shell variable is set, the shell lists the
       remaining choices (if any) whenever completion fails:

           > set autolist
           > nm /usr/lib/libt[tab]
           libtermcap.a@ libtermlib.a@
           > nm /usr/lib/libterm

       If autolist is set to `ambiguous', choices are listed only
       when completion fails and adds no new  characters  to  the
       word being completed.

       A filename to be completed can contain variables, your own
       or others' home  directories  abbreviated  with  `~'  (see
       Filename  substitution) and directory stack entries abbre-
       viated with `=' (see Directory  stack  substitution).  For
       example,

           > ls ~k[^D]
           kahn    kas     kellogg
           > ls ~ke[tab]
           > ls ~kellogg/

       or

           > set local = /usr/local
           > ls $lo[tab]
           > ls $local/[^D]
           bin/ etc/ lib/ man/ src/
           > ls $local/

       Note  that  variables can also be expanded explicitly with
       the expand-variables editor command.

       delete-char-or-list-or-eof only lists at the  end  of  the
       line;  in  the  middle  of a line it deletes the character
       under the cursor and on an empty line it logs one out  or,
       if  ignoreeof  is set, does nothing.  `M-^D', bound to the
       editor command list-choices, lists  completion  possibili-
       ties  anywhere  on a line, and list-choices (or any one of
       the related editor commands which do or don't delete, list
       and/or  log  out, listed under delete-char-or-list-or-eof)
       can be bound to `^D' with the bindkey builtin  command  if
       so desired.

       The  complete-word-fwd  and complete-word-back editor com-
       mands (not bound to any keys by default) can  be  used  to
       cycle  up  and  down  through the list of possible comple-
       tions, replacing the current word with the next or  previ-
       ous word in the list.

       The  shell  variable  fignore can be set to a list of suf-
       fixes to be ignored by completion. Consider the following:

           > ls
           Makefile        condiments.h~   main.o          side.c
           README          main.c          meal            side.o
           condiments.h    main.c~
           > set fignore = (.o \~)
           > emacs ma[^D]
           main.c   main.c~  main.o
           > emacs ma[tab]
           > emacs main.c

       `main.c~'  and `main.o' are ignored by completion (but not
       listing), because they end in suffixes in  fignore.   Note
       that  a  `\' was needed in front of `~' to prevent it from
       being expanded to home as described under Filename substi-
       tution.  fignore is ignored if only one completion is pos-
       sible.

       If the complete shell variable is set to  `enhance',  com-
       pletion  1) ignores case and 2) considers periods, hyphens
       and underscores (`.', `-' and `_') to be  word  separators
       and  hyphens  and underscores to be equivalent. If you had
       the following files

           comp.lang.c      comp.lang.perl   comp.std.c++
           comp.lang.c++    comp.std.c

       and typed `mail -f c.l.c[tab]', it would be  completed  to
       `mail -f comp.lang.c', and ^D would list `comp.lang.c' and
       `comp.lang.c++'.   `mail   -f   c..c++[^D]'   would   list
       `comp.lang.c++'    and    `comp.std.c++'.    Typing    `rm
       a--file[^D]' in the following directory

           A_silly_file                         a-hyphenated-file
           another_silly_file

       would  list  all  three files, because case is ignored and
       hyphens and underscores are equivalent. Periods,  however,
       are not equivalent to hyphens or underscores.

       Completion and listing are affected by several other shell
       variables: recexact can be set to complete on the shortest
       possible unique match, even if more typing might result in
       a longer match:

           > ls
           fodder   foo      food     foonly
           > set recexact
           > rm fo[tab]

       just beeps, because `fo' could expand to `fod'  or  `foo',
       but if we type another `o',

           > rm foo[tab]
           > rm foo

       the  completion completes on `foo', even though `food' and
       `foonly' also match.  autoexpand can be  set  to  run  the
       expand-history   editor  command  before  each  completion
       attempt, autocorrect can be set  to  spelling-correct  the
       word to be completed (see Spelling correction) before each
       completion attempt and correct can be set to complete com-
       mands  automatically  after  one hits `return'.  matchbeep
       can be set to make completion beep or not beep in a  vari-
       ety  of situations, and nobeep can be set to never beep at
       all.  nostat can be set to a list  of  directories  and/or
       patterns which match directories to prevent the completion
       mechanism from stat(2)ing those directories.  listmax  and
       listmaxrows  can  be  set to limit the number of items and
       rows (respectively) that are listed without asking  first.
       recognize_only_executables  can  be  set to make the shell
       list only executables when listing  commands,  but  it  is
       quite slow.

       Finally,  the complete builtin command can be used to tell
       the shell how to complete words other than filenames, com-
       mands  and  variables.  Completion and listing do not work
       on glob-patterns  (see  Filename  substitution),  but  the
       list-glob  and expand-glob editor commands perform equiva-
       lent functions for glob-patterns.

   Spelling correction (+)
       The shell can sometimes correct the spelling of filenames,
       commands  and  variable  names  as  well as completing and
       listing them.

       Individual words can be spelling-corrected with the spell-
       word editor command (usually bound to M-s and M-S) and the
       entire input buffer  with  spell-line  (usually  bound  to
       M-$).   The  correct shell variable can be set to `cmd' to
       correct the command name or `all' to  correct  the  entire
       line each time return is typed, and autocorrect can be set
       to correct the word to be completed before each completion
       attempt.

       When  spelling  correction is invoked in any of these ways
       and the shell thinks that any part of the command line  is
       misspelled, it prompts with the corrected line:

           > set correct = cmd
           > lz /usr/bin
           CORRECT>ls /usr/bin (y|n|e|a)?

       One can answer `y' or space to execute the corrected line,
       `e' to leave the uncorrected command in the input  buffer,
       `a' to abort the command as if `^C' had been hit, and any-
       thing else to execute the original line unchanged.

       Spelling correction  recognizes  user-defined  completions
       (see  the complete builtin command). If an input word in a
       position for which a completion  is  defined  resembles  a
       word in the completion list, spelling correction registers
       a misspelling and suggests the latter word  as  a  correc-
       tion. However, if the input word does not match any of the
       possible completions for that position,  spelling  correc-
       tion does not register a misspelling.

       Like completion, spelling correction works anywhere in the
       line, pushing the rest of the line to the right and possi-
       bly leaving extra characters to the right of the cursor.

       Beware:  spelling correction is not guaranteed to work the
       way one intends, and is provided mostly as an experimental
       feature.  Suggestions and improvements are welcome.

   Editor commands (+)
       `bindkey'  lists  key  bindings and `bindkey -l' lists and
       briefly describes editor commands.  Only new or especially
       interesting  editor  commands  are  described  here.   See
       emacs(1) and vi(1) for descriptions of each  editor's  key
       bindings.

       The character or characters to which each command is bound
       by default is given in parentheses. `^character'  means  a
       control  character  and  `M-character'  a  meta character,
       typed as escape-character on terminals without a meta key.
       Case  counts,  but  commands which are bound to letters by
       default are bound to both lower- and uppercase letters for
       convenience.

       complete-word (tab)
               Completes a word as described under Completion and
               listing.

       complete-word-back (not bound)
               Like complete-word-fwd, but steps up from the  end
               of the list.

       complete-word-fwd (not bound)
               Replaces  the  current word with the first word in
               the list of possible completions. May be  repeated
               to  step down through the list.  At the end of the
               list, beeps and reverts to the incomplete word.

       complete-word-raw (^X-tab)
               Like complete-word, but ignores user-defined  com-
               pletions.

       copy-prev-word (M-^_)
               Copies  the previous word in the current line into
               the input buffer.  See also insert-last-word.

       dabbrev-expand (M-/)
               Expands the current word to the most  recent  pre-
               ceding one for which the current is a leading sub-
               string, wrapping around the history list (once) if
               necessary.   Repeating  dabbrev-expand without any
               intervening typing changes to  the  next  previous
               word  etc.,  skipping  identical matches much like
               history-search-backward does.

       delete-char (not bound)
               Deletes the character under the cursor.  See  also
               delete-char-or-list-or-eof.

       delete-char-or-eof (not bound)
               Does delete-char if there is a character under the
               cursor or end-of-file on an empty line.  See  also
               delete-char-or-list-or-eof.

       delete-char-or-list (not bound)
               Does delete-char if there is a character under the
               cursor or list-choices at the  end  of  the  line.
               See also delete-char-or-list-or-eof.

       delete-char-or-list-or-eof (^D)
               Does delete-char if there is a character under the
               cursor, list-choices at the end  of  the  line  or
               end-of-file  on  an  empty  line.   See also those
               three commands, each of which only does  a  single
               action,  and  delete-char-or-eof,  delete-char-or-
               list and list-or-eof, each of which does a differ-
               ent two out of the three.

       down-history (down-arrow, ^N)
               Like  up-history,  but steps down, stopping at the
               original input line.

       end-of-file (not bound)
               Signals an end of file, causing the shell to  exit
               unless  the ignoreeof shell variable (q.v.) is set
               to prevent this.  See also delete-char-or-list-or-
               eof.

       expand-history (M-space)
               Expands history substitutions in the current word.
               See History substitution.  See  also  magic-space,
               toggle-literal-history  and  the  autoexpand shell
               variable.

       expand-glob (^X-*)
               Expands the glob-pattern to the left of  the  cur-
               sor.  See Filename substitution.

       expand-line (not bound)
               Like expand-history, but expands history substitu-
               tions in each word in the input buffer,

       expand-variables (^X-$)
               Expands the variable to the left  of  the  cursor.
               See Variable substitution.

       history-search-backward (M-p, M-P)
               Searches  backwards through the history list for a
               command beginning with the current contents of the
               input  buffer  up to the cursor and copies it into
               the input buffer.  The  search  string  may  be  a
               glob-pattern  (see Filename substitution) contain-
               ing `*', `?', `[]' or `{}'.  up-history and  down-
               history will proceed from the appropriate point in
               the history list.  Emacs mode only.  See also his-
               tory-search-forward and i-search-back.

       history-search-forward (M-n, M-N)
               Like  history-search-backward,  but  searches for-
               ward.

       i-search-back (not bound)
               Searches  backward  like  history-search-backward,
               copies  the first match into the input buffer with
               the cursor positioned at the end of  the  pattern,
               and  prompts  with  `bck:  '  and the first match.
               Additional characters may be typed to  extend  the
               search,  i-search-back  may  be  typed to continue
               searching with the same pattern,  wrapping  around
               the history list if necessary, (i-search-back must
               be bound to a single character for this  to  work)
               or  one of the following special characters may be
               typed:

                   ^W      Appends the rest of the word under the
                           cursor to the search pattern.
                   delete (or any character bound to backward-
                           delete-char)
                           Undoes the effect of the last  charac-
                           ter typed and deletes a character from
                           the search pattern if appropriate.
                   ^G      If the previous search was successful,
                           aborts  the  entire  search.   If not,
                           goes  back  to  the  last   successful
                           search.
                   escape  Ends  the  search, leaving the current
                           line in the input buffer.

               Any other character not bound to  self-insert-com-
               mand  terminates  the  search, leaving the current
               line in the input buffer, and is then  interpreted
               as  normal input. In particular, a carriage return
               causes the current line  to  be  executed.   Emacs
               mode  only.   See  also  i-search-fwd and history-
               search-backward.

       i-search-fwd (not bound)
               Like i-search-back, but searches forward.

       insert-last-word (M-_)
               Inserts the last word of the previous  input  line
               (`!$') into the input buffer.  See also copy-prev-
               word.

       list-choices (M-^D)
               Lists completion possibilities as described  under
               Completion  and listing.  See also delete-char-or-
               list-or-eof and list-choices-raw.

       list-choices-raw (^X-^D)
               Like list-choices, but ignores  user-defined  com-
               pletions.

       list-glob (^X-g, ^X-G)
               Lists  (via the ls-F builtin) matches to the glob-
               pattern (see Filename substitution) to the left of
               the cursor.

       list-or-eof (not bound)
               Does list-choices or end-of-file on an empty line.
               See also delete-char-or-list-or-eof.

       magic-space (not bound)
               Expands history substitutions in the current line,
               like  expand-history, and appends a space.  magic-
               space is designed to be bound to the spacebar, but
               is not bound by default.

       normalize-command (^X-?)
               Searches  for  the current word in PATH and, if it
               is found, replaces it with the full  path  to  the
               executable. Special characters are quoted. Aliases
               are  expanded  and  quoted  but  commands   within
               aliases  are not. This command is useful with com-
               mands which take commands as arguments, e.g. `dbx'
               and `sh -x'.

       normalize-path (^X-n, ^X-N)
               Expands  the  current  word as described under the
               `expand' setting of the symlinks shell variable.

       overwrite-mode (unbound)
               Toggles between input and overwrite modes.

       run-fg-editor (M-^Z)
               Saves the current  input  line  and  looks  for  a
               stopped  job  with a name equal to the last compo-
               nent of the file name part of the EDITOR or VISUAL
               environment variables, or, if neither is set, `ed'
               or `vi'.  If such a job is found, it is  restarted
               as  if  `fg %job' had been typed.  This is used to
               toggle back and forth between an  editor  and  the
               shell  easily.   Some  people bind this command to
               `^Z' so they can do this even more easily.

       run-help (M-h, M-H)
               Searches for documentation on the current command,
               using  the same notion of `current command' as the
               completion routines, and prints it.  There  is  no
               way to use a pager; run-help is designed for short
               help files.  Documentation should  be  in  a  file
               named  command.help,  command.1,  command.6,  com-
               mand.8 or command, which should be in one  of  the
               directories  listed  in the HPATH enviroment vari-
               able.  If there is more than one  help  file  only
               the first is printed.

       self-insert-command (text characters)
               In  insert  mode  (the default), inserts the typed
               character into the input line after the  character
               under the cursor.  In overwrite mode, replaces the
               character under the cursor with the typed  charac-
               ter.  The input mode is normally preserved between
               lines, but the inputmode shell variable can be set
               to  `insert'  or  `overwrite' to put the editor in
               that mode at the beginning of each line.  See also
               overwrite-mode.

       sequence-lead-in (arrow prefix, meta prefix, ^X)
               Indicates  that  the following characters are part
               of a multi-key sequence. Binding a  command  to  a
               multi-key  sequence  really  creates two bindings:
               the first character to  sequence-lead-in  and  the
               whole  sequence  to  the  command.  All  sequences
               beginning with a character bound to sequence-lead-
               in  are  effectively bound to undefined-key unless
               bound to another command.

       spell-line (M-$)
               Attempts to correct the spelling of each  word  in
               the  input  buffer,  like  spell-word, but ignores
               words whose first character is one  of  `-',  `!',
               `^'  or  `%', or which contain `\', `*' or `?', to
               avoid problems with  switches,  substitutions  and
               the like.  See Spelling correction.

       spell-word (M-s, M-S)
               Attempts  to  correct  the spelling of the current
               word  as  described  under  Spelling   correction.
               Checks  each  component of a word which appears to
               be a pathname.

       toggle-literal-history (M-r, M-R)
               Expands or `unexpands'  history  substitutions  in
               the input buffer.  See also expand-history and the
               autoexpand shell variable.

       undefined-key (any unbound key)
               Beeps.

       up-history (up-arrow, ^P)
               Copies the previous entry in the history list into
               the  input  buffer.   If  histlit is set, uses the
               literal form of the entry.   May  be  repeated  to
               step  up through the history list, stopping at the
               top.

       vi-search-back (?)
               Prompts with `?' for a search string (which may be
               a  glob-pattern, as with history-search-backward),
               searches for it  and  copies  it  into  the  input
               buffer. The bell rings if no match is found.  Hit-
               ting return ends the search and  leaves  the  last
               match  in  the  input buffer.  Hitting escape ends
               the search and executes the match.  vi mode  only.

       vi-search-fwd (/)
               Like vi-search-back, but searches forward.

       which-command (M-?)
               Does  a  which (see the description of the builtin
               command) on the first word of the input buffer.

   Lexical structure
       The shell splits input lines  into  words  at  blanks  and
       tabs.   The  special  characters  `&', `|', `;', `<', `>',
       `(', and `)' and the doubled characters `&&',  `||',  `<<'
       and  `>>'  are  always separate words, whether or not they
       are surrounded by whitespace.

       When the shell's input is not a  terminal,  the  character
       `#'  is taken to begin a comment. Each `#' and the rest of
       the input line on which it  appears  is  discarded  before
       further parsing.

       A special character (including a blank or tab) may be pre-
       vented from having its special meaning, and possibly  made
       part  of  another  word,  by preceding it with a backslash
       (`\') or enclosing it in single  (`''),  double  (`"')  or
       backward (``') quotes. When not otherwise quoted a newline
       preceded by a `\' is equivalent to  a  blank,  but  inside
       quotes this sequence results in a newline.

       Furthermore,  all Substitutions (see below) except History
       substitution can be prevented by enclosing the strings (or
       parts  of strings) in which they appear with single quotes
       or by quoting the crucial character(s) (e.g.  `$'  or  ``'
       for  Variable substitution or Command substitution respec-
       tively) with `\'. (Alias  substitution  is  no  exception:
       quoting  in  any  way any character of a word for which an
       alias has been defined prevents substitution of the alias.
       The  usual way of quoting an alias is to precede it with a
       backslash.) History substitution  is  prevented  by  back-
       slashes  but  not  by  single quotes.  Strings quoted with
       double or backward quotes  undergo  Variable  substitution
       and Command substitution, but other substitutions are pre-
       vented.

       Text inside single or double quotes becomes a single  word
       (or  part  of  one).   Metacharacters  in  these  strings,
       including blanks and tabs, do  not  form  separate  words.
       Only  in one special case (see Command substitution below)
       can a double-quoted string yield parts of  more  than  one
       word;  single-quoted strings never do. Backward quotes are
       special: they signal Command  substitution  (q.v.),  which
       may result in more than one word.

       Quoting  complex strings, particularly strings which them-
       selves  contain  quoting  characters,  can  be  confusing.
       Remember that quotes need not be used as they are in human
       writing! It may be easier to quote not an  entire  string,
       but  only  those  parts  of the string which need quoting,
       using different types of quoting to do so if  appropriate.

       The  backslash_quote  shell  variable (q.v.) can be set to
       make backslashes always quote `\', `'', and `"'. (+)  This
       may  make  complex  quoting tasks easier, but it can cause
       syntax errors in csh(1) scripts.

   Substitutions
       We now describe the various transformations the shell per-
       forms  on  the  input in the order in which they occur. We
       note in passing the data structures involved and the  com-
       mands  and variables which affect them. Remember that sub-
       stitutions can be prevented by quoting as described  under
       Lexical structure.

   History substitution
       Each  command,  or  ``event'',  input from the terminal is
       saved in the history list.  The previous command is always
       saved, and the history shell variable can be set to a num-
       ber to save that many commands. The histdup shell variable
       can  be  set  to  not save duplicate events or consecutive
       duplicate events.

       Saved  commands  are  numbered  sequentially  from  1  and
       stamped with the time.  It is not usually necessary to use
       event numbers, but the current event number  can  be  made
       part  of  the prompt by placing an `!' in the prompt shell
       variable.

       The shell actually saves history in expanded  and  literal
       (unexpanded) forms.  If the histlit shell variable is set,
       commands that display and store history  use  the  literal
       form.

       The  history  builtin  command can print, store in a file,
       restore and clear the history list at any  time,  and  the
       savehist and histfile shell variables can be can be set to
       store the history list automatically on logout and restore
       it on login.

       History  substitutions  introduce  words  from the history
       list into the input stream, making it easy to repeat  com-
       mands,  repeat arguments of a previous command in the cur-
       rent command, or fix spelling  mistakes  in  the  previous
       command  with  little  typing  and a high degree of confi-
       dence.

       History substitutions begin with the character  `!'.  They
       may  begin  anywhere  in the input stream, but they do not
       nest.  The `!' may be preceded by a  `\'  to  prevent  its
       special   meaning;   for  convenience,  a  `!'  is  passed
       unchanged when it is followed by a  blank,  tab,  newline,
       `='  or  `('.   History  substitutions  also occur when an
       input line begins with  `^'.   This  special  abbreviation
       will  be  described  later.  The characters used to signal
       history substitution (`!' and `^') can be changed by  set-
       ting  the  histchars  shell variable. Any input line which
       contains a history substitution is printed  before  it  is
       executed.

       A  history  substitution  may  have  an ``event specifica-
       tion'', which indicates the event from which words are  to
       be  taken, a ``word designator'', which selects particular
       words from the chosen event, and/or a ``modifier'',  which
       manipulates the selected words.

       An event specification can be

           n       A number, referring to a particular event
           -n      An offset, referring to the event n before the
                   current event
           #       The current event.  This should be used  care-
                   fully  in  csh(1), where there is no check for
                   recursion. tcsh allows 10 levels of recursion.
                   (+)
           !       The previous event (equivalent to `-1')
           s       The  most recent event whose first word begins
                   with the string s
           ?s?     The  most  recent  event  which  contains  the
                   string s.  The second `?' can be omitted if it
                   is immediately followed by a newline.

       For example, consider this bit of someone's history list:

            9  8:30    nroff -man wumpus.man
           10  8:31    cp wumpus.man wumpus.man.old
           11  8:36    vi wumpus.man
           12  8:37    diff wumpus.man.old wumpus.man

       The commands are shown with their event numbers  and  time
       stamps.  The current event, which we haven't typed in yet,
       is event 13.  `!11' and `!-2' refer  to  event  11.   `!!'
       refers  to the previous event, 12. `!!' can be abbreviated
       `!' if it is followed by `:'  (`:'  is  described  below).
       `!n'  refers  to event 9, which begins with `n'.  `!?old?'
       also refers to event 12, which  contains  `old'.   Without
       word  designators  or  modifiers history references simply
       expand to the entire event, so we might type `!cp' to redo
       the  copy  command  or  `!!|more'  if  the  `diff'  output
       scrolled off the top of the screen.

       History references may be insulated from  the  surrounding
       text with braces if necessary.  For example, `!vdoc' would
       look for a command beginning with  `vdoc',  and,  in  this
       example,  not  find  one, but `!{v}doc' would expand unam-
       biguously to `vi wumpus.mandoc'.  Even in braces,  history
       substitutions do not nest.

       (+)  While  csh(1)  expands, for example, `!3d' to event 3
       with the letter `d' appended to it, tcsh expands it to the
       last  event  beginning  with `3d'; only completely numeric
       arguments are treated as event  numbers.   This  makes  it
       possible  to  recall  events  beginning  with numbers.  To
       expand `!3d' as in csh(1) say `!\3d'.

       To select words from an event  we  can  follow  the  event
       specification  by  a  `:' and a designator for the desired
       words.  The words of an input line are  numbered  from  0,
       the  first (usually command) word being 0, the second word
       (first argument) being 1, etc. The basic word  designators
       are:

           0       The first (command) word
           n       The nth argument
           ^       The first argument, equivalent to `1'
           $       The last argument
           %       The word matched by an ?s? search
           x-y     A range of words
           -y      Equivalent to `0-y'
           *       Equivalent  to  `^-$',  but returns nothing if
                   the event contains only 1 word
           x*      Equivalent to `x-$'
           x-      Equivalent to `x*', but omitting the last word
                   (`$')

       Selected  words  are  inserted into the command line sepa-
       rated by single blanks.  For example, the  `diff'  command
       in  the  previous  example  might have been typed as `diff
       !!:1.old !!:1' (using `:1' to select  the  first  argument
       from  the  previous event) or `diff !-2:2 !-2:1' to select
       and swap the arguments from the `cp' command. If we didn't
       care  about  the  order  of  the `diff' we might have said
       `diff !-2:1-2' or simply `diff !-2:*'.  The  `cp'  command
       might  have  been  written `cp wumpus.man !#:1.old', using
       `#' to refer to  the  current  event.   `!n:-  hurkle.man'
       would  reuse  the first two words from the `nroff' command
       to say `nroff -man hurkle.man'.

       The `:' separating the event specification from  the  word
       designator  can be omitted if the argument selector begins
       with a `^', `$', `*', `%' or `-'.  For example, our `diff'
       command  might  have  been  `diff !!^.old !!^' or, equiva-
       lently, `diff !!$.old !!$'. However, if `!!'  is  abbrevi-
       ated  `!', an argument selector beginning with `-' will be
       interpreted as an event specification.

       A history reference may have  a  word  designator  but  no
       event specification.  It then references the previous com-
       mand.  Continuing our `diff' example, we could  have  said
       simply  `diff  !^.old  !^' or, to get the arguments in the
       opposite order, just `diff !*'.

       The word or words in a history reference can be edited, or
       ``modified'',  by following it with one or more modifiers,
       each preceded by a `:':

           h       Remove a trailing pathname component,  leaving
                   the head.
           t       Remove  all leading pathname components, leav-
                   ing the tail.
           r       Remove a filename  extension  `.xxx',  leaving
                   the root name.
           e       Remove all but the extension.
           u       Uppercase the first lowercase letter.
           l       Lowercase the first uppercase letter.
           s/l/r/  Substitute l for r.  l is simply a string like
                   r, not a regular expression as in  the  epony-
                   mous ed(1) command.  Any character may be used
                   as the delimiter in place of `/'; a `\' can be
                   used  to  quote  the delimiter inside l and r.
                   The character `&' in the r is replaced  by  l;
                   `\'  also  quotes  `&'.  If l is empty (``''),
                   the l from a previous substitution  or  the  s
                   from  a  previous `?s?' event specification is
                   used.  The trailing delimiter may  be  omitted
                   if it is immediately followed by a newline.
           &       Repeat the previous substitution.
           g       Apply  the  following  modifier  once  to each
                   word.
           a (+)   Apply the following modifier as many times  as
                   possible to a single word.  `a' and `g' can be
                   used together to apply  a  modifier  globally.
                   In  the  current implementation, using the `a'
                   and `s' modifiers  together  can  lead  to  an
                   infinite  loop.  For example, `:as/f/ff/' will
                   never terminate.  This behavior  might  change
                   in the future.
           p       Print  the new command line but do not execute
                   it.
           q       Quote the substituted words,  preventing  fur-
                   ther substitutions.
           x       Like  q,  but break into words at blanks, tabs
                   and newlines.

       Modifiers are applied only to the  first  modifiable  word
       (unless  `g'  is  used).  It is an error for no word to be
       modifiable.

       For example, the `diff' command might have been written as
       `diff  wumpus.man.old  !#^:r', using `:r' to remove `.old'
       from the first argument on the same line (`!#^'). We could
       say `echo hello out there', then `echo !*:u' to capitalize
       `hello', `echo !*:au' to say it out loud, or `echo !*:agu'
       to  really  shout.   We might follow `mail -s "I forgot my
       password" rot' with `!:s/rot/root' to correct the spelling
       of  `root'  (but  see  Spelling correction for a different
       approach).

       There is a special abbreviation for  substitutions.   `^',
       when it is the first character on an input line, is equiv-
       alent to `!:s^'.  Thus we might have said  `^rot^root'  to
       make  the  spelling  correction  in  the previous example.
       This is the  only  history  substitution  which  does  not
       explicitly begin with `!'.

       (+)  In  csh  as such, only one modifier may be applied to
       each history or variable expansion. In tcsh, more than one
       may be used, for example

           % mv wumpus.man /usr/man/man1/wumpus.1
           % man !$:t:r
           man wumpus

       In  csh,  the result would be `wumpus.1:r'. A substitution
       followed by a colon may need to be insulated from it  with
       braces:

           > mv a.out /usr/games/wumpus
           > setenv PATH !$:h:$PATH
           Bad ! modifier: $.
           > setenv PATH !{-2$:h}:$PATH
           setenv PATH /usr/games:/bin:/usr/bin:.

       The  first attempt would succeed in csh but fails in tcsh,
       because tcsh expects another  modifier  after  the  second
       colon rather than `$'.

       Finally,  history  can  be  accessed through the editor as
       well as through the substitutions just described.  The up-
       and down-history, history-search-backward and -forward, i-
       search-back and -fwd, vi-search-back and -fwd,  copy-prev-
       word  and  insert-last-word  editor  commands  search  for
       events in the history list and copy them  into  the  input
       buffer.    The   toggle-literal-history   editor   command
       switches between the expanded and literal forms of history
       lines in the input buffer.  expand-history and expand-line
       expand history substitutions in the current  word  and  in
       the entire input buffer respectively.

   Alias substitution
       The  shell  maintains  a list of aliases which can be set,
       unset and printed  by  the  alias  and  unalias  commands.
       After  a  command line is parsed into simple commands (see
       Commands) the first word of each  command,  left-to-right,
       is  checked  to  see if it has an alias.  If so, the first
       word is replaced by the alias. If  the  alias  contains  a
       history   reference,  it  undergoes  History  substitution
       (q.v.) as though the original command  were  the  previous
       input line. If the alias does not contain a history refer-
       ence, the argument list is left untouched.

       Thus if the alias for `ls' were `ls -l'  the  command  `ls
       /usr'  would  become  `ls -l /usr', the argument list here
       being undisturbed.  If the alias for `lookup'  were  `grep
       !^ /etc/passwd' then `lookup bill' would become `grep bill
       /etc/passwd'.  Aliases can be  used  to  introduce  parser
       metasyntax.   For  example,  `alias  print 'pr \!* | lpr''
       defines a ``command'' (`print') which pr(1)s its arguments
       to the line printer.

       Alias substitution is repeated until the first word of the
       command has no alias. If an alias  substitution  does  not
       change  the  first word (as in the previous example) it is
       flagged to prevent a loop. Other loops  are  detected  and
       cause an error.

       Some  aliases  are  referred  to by the shell; see Special
       aliases.

   Variable substitution
       The shell maintains a list of variables, each of which has
       as  value  a  list  of  zero or more words.  The values of
       shell variables can be displayed and changed with the  set
       and  unset commands.  The system maintains its own list of
       ``environment'' variables.  These  can  be  displayed  and
       changed with printenv, setenv and unsetenv.

       (+)  Variables  may be made read-only with `set -r' (q.v.)
       Read-only variables may not be modified or unset; attempt-
       ing  to do so will cause an error.  Once made read-only, a
       variable cannot be made writable, so `set  -r'  should  be
       used  with  caution.  Environment variables cannot be made
       read-only.

       Some variables are set by the shell or referred to by  it.
       For instance, the argv variable is an image of the shell's
       argument list, and words  of  this  variable's  value  are
       referred  to  in  special  ways.   Some  of  the variables
       referred to by the shell are toggles; the shell  does  not
       care  what  their  value  is, only whether they are set or
       not.  For instance, the verbose variable is a toggle which
       causes  command  input  to be echoed.  The -v command line
       option sets this variable.  Special shell variables  lists
       all variables which are referred to by the shell.

       Other  operations  treat  variables  numerically.  The `@'
       command permits numeric calculations to be  performed  and
       the  result  assigned to a variable.  Variable values are,
       however, always represented as  (zero  or  more)  strings.
       For the purposes of numeric operations, the null string is
       considered to be zero, and the second and subsequent words
       of multiword values are ignored.

       After  the  input  line  is aliased and parsed, and before
       each command is executed, variable  substitution  is  per-
       formed  keyed  by  `$'  characters.  This expansion can be
       prevented by preceding the `$' with a  `\'  except  within
       `"'s  where  it  always  occurs,  and within `''s where it
       never occurs.  Strings quoted by ``' are interpreted later
       (see  Command substitution below) so `$' substitution does
       not occur there until later, if at all.  A `$'  is  passed
       unchanged if followed by a blank, tab, or end-of-line.

       Input/output  redirections  are recognized before variable
       expansion, and are variable expanded  separately.   Other-
       wise,  the  command  name  and  entire  argument  list are
       expanded together.  It is  thus  possible  for  the  first
       (command)  word  (to this point) to generate more than one
       word, the first of which becomes the command name, and the
       rest of which become arguments.

       Unless  enclosed  in  `"'  or  given the `:q' modifier the
       results of variable substitution may eventually be command
       and  filename  substituted.   Within `"', a variable whose
       value consists of multiple words expands to a (portion  of
       a)  single  word,  with  the words of the variable's value
       separated by blanks.  When the `:q' modifier is applied to
       a  substitution the variable will expand to multiple words
       with each word separated by a blank and quoted to  prevent
       later command or filename substitution.

       The  following  metasequences are provided for introducing
       variable values into the shell input.  Except as noted, it
       is an error to reference a variable which is not set.

       $name
       ${name} Substitutes  the  words  of  the value of variable
               name, each separated by a blank.  Braces  insulate
               name  from following characters which would other-
               wise be part of it.  Shell  variables  have  names
               consisting of up to 20 letters and digits starting
               with a letter.  The underscore character  is  con-
               sidered  a  letter.   If name is not a shell vari-
               able, but is set in  the  environment,  then  that
               value is returned (but `:' modifiers and the other
               forms given below are not available in this case).
       $name[selector]
       ${name[selector]}
               Substitutes only the selected words from the value
               of name.  The selector is subjected to `$' substi-
               tution  and  may consist of a single number or two
               numbers separated by a `-'.  The first word  of  a
               variable's  value  is  numbered `1'.  If the first
               number of a range is omitted it defaults  to  `1'.
               If  the  last  member  of  a  range  is omitted it
               defaults to `$#name'.  The  selector  `*'  selects
               all  words.   It is not an error for a range to be
               empty if the second  argument  is  omitted  or  in
               range.
       $0      Substitutes  the  name of the file from which com-
               mand input is being read.  An error occurs if  the
               name is not known.
       $number
       ${number}
               Equivalent to `$argv[number]'.
       $*      Equivalent  to  `$argv',  which  is  equivalent to
               `$argv[*]'.

       The `:' modifiers described  under  History  substitution,
       except  for  `:p',  can  be  applied  to the substitutions
       above. More than one may be used. (+) Braces may be needed
       to  insulate  a variable substitution from a literal colon
       just as with History substitution  (q.v.);  any  modifiers
       must appear within the braces.

       The  following  substitutions can not be modified with `:'
       modifiers.

       $?name
       ${?name}
               Substitutes the string `1' if name is set, `0'  if
               it is not.
       $?0     Substitutes  `1'  if the current input filename is
               known, `0' if it is not.  Always `0'  in  interac-
               tive shells.
       $#name
       ${#name}
               Substitutes the number of words in name.
       $#      Equivalent to `$#argv'. (+)
       $%name
       ${%name}
               Substitutes the number of characters in name. (+)
       $%number
       ${%number}
               Substitutes the number of characters in $argv[num-
               ber]. (+)
       $?      Equivalent to `$status'. (+)
       $$      Substitutes the (decimal) process  number  of  the
               (parent) shell.
       $!      Substitutes  the  (decimal)  process number of the
               last background process started by this shell.
       $<      Substitutes a line from the standard  input,  with
               no  further  interpretation thereafter.  It can be
               used to read from the keyboard in a shell  script.
               (+)  While  csh  always  quotes  $<, as if it were
               equivalent to `$<:q', tcsh does not.  Furthermore,
               when  tcsh  is  waiting for a line to be typed the
               user  may  type  an  interrupt  to  interrupt  the
               sequence into which the line is to be substituted,
               but csh does not allow this.

       The editor command  expand-variables,  normally  bound  to
       `^X-$',  can  be  used  to interactively expand individual
       variables.

   Command, filename and directory stack substitution
       The remaining substitutions are applied selectively to the
       arguments  of  builtin commands.  This means that portions
       of expressions which are not evaluated are  not  subjected
       to  these expansions.  For commands which are not internal
       to the shell, the command name is  substituted  separately
       from  the  argument  list.   This  occurs very late, after
       input-output redirection is performed, and in a  child  of
       the main shell.

   Command substitution
       Command substitution is indicated by a command enclosed in
       ``'.  The output from such a command is broken into  sepa-
       rate  words  at  blanks, tabs and newlines, and null words
       are discarded. The output is variable and command  substi-
       tuted and put in place of the original string.

       Command  substitutions  inside  double quotes (`"') retain
       blanks and tabs; only newlines force new words.  The  sin-
       gle  final  newline does not force a new word in any case.
       It is thus possible for a command  substitution  to  yield
       only  part  of  a word, even if the command outputs a com-
       plete line.

   Filename substitution
       If a word contains any of the characters `*', `?', `['  or
       `{' or begins with the character `~' it is a candidate for
       filename substitution, also known  as  ``globbing''.  This
       word is then regarded as a pattern (``glob-pattern''), and
       replaced with an alphabetically sorted list of file  names
       which match the pattern.

       In  matching filenames, the character `.' at the beginning
       of a filename or immediately following a `/', as  well  as
       the character `/' must be matched explicitly.  The charac-
       ter `*' matches any string of  characters,  including  the
       null string.  The character `?' matches any single charac-
       ter.  The sequence `[...]' matches any one of the  charac-
       ters enclosed.  Within `[...]', a pair of characters sepa-
       rated by `-' matches any character lexically  between  the
       two.

       (+)  Some  glob-patterns  can  be  negated:  The  sequence
       `[^...]' matches any single character not specified by the
       characters and/or ranges of characters in the braces.

       An entire glob-pattern can also be negated with `^':

           > echo *
           bang crash crunch ouch
           > echo ^cr*
           bang ouch

       Glob-patterns  which do not use `?', `*', or `[]' or which
       use `{}' or `~' (below) are not negated correctly.

       The metanotation `a{b,c,d}e' is a shorthand for  `abe  ace
       ade'.       Left-to-right      order     is     preserved:
       `/usr/source/s1/{oldls,ls}.c'          expands          to
       `/usr/source/s1/oldls.c  /usr/source/s1/ls.c'. The results
       of matches are sorted separately at a low  level  to  pre-
       serve   this   order:  `../{memo,*box}'  might  expand  to
       `../memo ../box  ../mbox'.   (Note  that  `memo'  was  not
       sorted with the results of matching `*box'.)  It is not an
       error when this construct expands to files  which  do  not
       exist,  but  it is possible to get an error from a command
       to which the expanded list is passed.  This construct  may
       be  nested.  As a special case the words `{', `}' and `{}'
       are passed undisturbed.

       The character `~' at the beginning of a filename refers to
       home directories.  Standing alone, i.e. `~', it expands to
       the invoker's home directory as reflected in the value  of
       the  home shell variable. When followed by a name consist-
       ing of  letters,  digits  and  `-'  characters  the  shell
       searches  for  a user with that name and substitutes their
       home directory; thus `~ken' might expand to `/usr/ken' and
       `~ken/chmach'  to `/usr/ken/chmach'.  If the character `~'
       is followed by a character other than a letter or  `/'  or
       appears  elsewhere  than at the beginning of a word, it is
       left  undisturbed.   A  command   like   `setenv   MANPATH
       /usr/man:/usr/local/man:~/lib/man' does not, therefore, do
       home directory substitution as one might hope.

       It is an error for a glob-pattern containing `*', `?', `['
       or  `~', with or without `^', not to match any files. How-
       ever, only one pattern in a  list  of  glob-patterns  must
       match  a  file (so that, e.g., `rm *.a *.c *.o' would fail
       only if there were no files in the current directory  end-
       ing  in  `.a',  `.c', or `.o'), and if the nonomatch shell
       variable is set a pattern  (or  list  of  patterns)  which
       matches  nothing  is left unchanged rather than causing an
       error.

       The noglob shell variable can be set to  prevent  filename
       substitution, and the expand-glob editor command, normally
       bound to `^X-*', can be used to interactively expand indi-
       vidual filename substitutions.

   Directory stack substitution (+)
       The  directory  stack  is  a list of directories, numbered
       from zero, used by the pushd, popd and dirs  builtin  com-
       mands  (q.v.).   dirs  can print, store in a file, restore
       and clear  the  directory  stack  at  any  time,  and  the
       savedirs  and dirsfile shell variables can be set to store
       the directory stack automatically on logout and restore it
       on  login.  The dirstack shell variable can be examined to
       see the directory stack and set to put arbitrary  directo-
       ries into the directory stack.

       The  character  `=' followed by one or more digits expands
       to an entry in the directory stack. The special case  `=-'
       expands to the last directory in the stack. For example,

           > dirs -v
           0       /usr/bin
           1       /usr/spool/uucp
           2       /usr/accts/sys
           > echo =1
           /usr/spool/uucp
           > echo =0/calendar
           /usr/bin/calendar
           > echo =-
           /usr/accts/sys

       The  noglob  and nonomatch shell variables and the expand-
       glob editor command apply to directory stack  as  well  as
       filename substitutions.

   Other substitutions (+)
       There  are  several  more  transformations involving file-
       names, not strictly related to  the  above  but  mentioned
       here  for completeness.  Any filename may be expanded to a
       full path when the symlinks  variable  (q.v.)  is  set  to
       `expand'.   Quoting  prevents this expansion, and the nor-
       malize-path editor command does it on demand.  The normal-
       ize-command  editor  command expands commands in PATH into
       full paths on demand.  Finally, cd and pushd interpret `-'
       as  the  old  working  directory  (equivalent to the shell
       variable owd).  This is not a substitution at all, but  an
       abbreviation  recognized  only by those commands. Nonethe-
       less, it too can be prevented by quoting.

   Commands
       The next three sections describe how  the  shell  executes
       commands and deals with their input and output.

   Simple commands, pipelines and sequences
       A  simple  command  is  a  sequence of words, the first of
       which specifies the command to be executed.  A  series  of
       simple commands joined by `|' characters forms a pipeline.
       The output of each command in a pipeline is  connected  to
       the input of the next.

       Simple commands and pipelines may be joined into sequences
       with `;', and will be executed sequentially.  Commands and
       pipelines  can  also be joined into sequences with `||' or
       `&&', indicating, as in the C language, that the second is
       to be executed only if the first fails or succeeds respec-
       tively.

       A simple command, pipeline or sequence may  be  placed  in
       parentheses,  `()', to form a simple command, which may in
       turn be a component of a pipeline or sequence. A  command,
       pipeline  or  sequence can be executed without waiting for
       it to terminate by following it with an `&'.

   Builtin and non-builtin command execution
       Builtin commands are executed within the  shell.   If  any
       component  of a pipeline except the last is a builtin com-
       mand, the pipeline is executed in a subshell.

       Parenthesized commands are always executed in a  subshell.

           (cd; pwd); pwd

       thus prints the home directory, leaving you where you were
       (printing this after the home directory), while

           cd; pwd

       leaves you in the home directory.  Parenthesized  commands
       are  most often used to prevent cd from affecting the cur-
       rent shell.

       When a command to be executed is found not to be a builtin
       command  the  shell  attempts  to  execute the command via
       execve(2).  Each word in the variable path names a  direc-
       tory  in which the shell will look for the command.  If it
       is given neither a -c nor a -t option,  the  shell  hashes
       the  names  in these directories into an internal table so
       that it will only try an execve(2) in a directory if there
       is  a  possibility  that  the command resides there.  This
       greatly speeds command location when  a  large  number  of
       directories are present in the search path.  If this mech-
       anism has been turned off (via unhash), if the  shell  was
       given  a  -c or -t argument or in any case for each direc-
       tory component of path which does not begin  with  a  `/',
       the  shell concatenates the current working directory with
       the given command name to form a path name of a file which
       it then attempts to execute.

       If  the  file  has  execute permissions but is not an exe-
       cutable to the system (i.e. it is  neither  an  executable
       binary nor a script which specifies its interpreter), then
       it is assumed to be a file containing shell commands and a
       new  shell  is spawned to read it. The shell special alias
       may be set to specify an interpreter other than the  shell
       itself.

       On  systems which do not understand the `#!' script inter-
       preter convention the shell may be compiled to emulate it;
       see  the  version  shell variable. If so, the shell checks
       the first line of the file to see if it  is  of  the  form
       `#!interpreter arg ...'. If it is, the shell starts inter-
       preter with the given args and feeds the  file  to  it  on
       standard input.

   Input/output
       The standard input and standard output of a command may be
       redirected with the following syntax:

       < name  Open file name (which is first  variable,  command
               and filename expanded) as the standard input.
       << word Read the shell input up to a line which is identi-
               cal to word. word is not  subjected  to  variable,
               filename  or  command substitution, and each input
               line is compared to word before any  substitutions
               are  done  on  this  input line.  Unless a quoting
               `\', `"', `' or ``' appears in word  variable  and
               command substitution is performed on the interven-
               ing lines, allowing `\' to quote `$', `\' and ``'.
               Commands  which  are  substituted have all blanks,
               tabs, and newlines preserved, except for the final
               newline  which  is dropped.  The resultant text is
               placed in an anonymous  temporary  file  which  is
               given to the command as standard input.
       > name
       >! name
       >& name
       >&! name
               The  file name is used as standard output.  If the
               file does not exist then it  is  created;  if  the
               file  exists,  its is truncated, its previous con-
               tents being lost.

               If the shell variable noclobber is set,  then  the
               file must not exist or be a character special file
               (e.g. a  terminal  or  `/dev/null')  or  an  error
               results.   This  helps prevent accidental destruc-
               tion of files.  In this case the `!' forms can  be
               used to suppress this check.

               The  forms involving `&' route the diagnostic out-
               put into the specified file as well as  the  stan-
               dard  output.  name is expanded in the same way as
               `<' input filenames are.
       >> name
       >>& name
       >>! name
       >>&! name
               Like `>', but appends output to the end  of  name.
               If the shell variable noclobber is set, then it is
               an error for the file not to exist, unless one  of
               the `!' forms is given.

       A  command receives the environment in which the shell was
       invoked as modified by the input-output parameters and the
       presence  of the command in a pipeline.  Thus, unlike some
       previous shells, commands run from a file  of  shell  com-
       mands  have  no  access  to  the  text  of the commands by
       default; rather they receive the original  standard  input
       of  the  shell.  The `<<' mechanism should be used to pre-
       sent inline data.  This permits shell command  scripts  to
       function  as  components of pipelines and allows the shell
       to block read its input.  Note that the  default  standard
       input  for  a  command  run detached is not the empty file
       /dev/null, but the original standard input of  the  shell.
       If  this is a terminal and if the process attempts to read
       from the terminal, then the process  will  block  and  the
       user will be notified (see Jobs).

       Diagnostic  output may be directed through a pipe with the
       standard output.  Simply use the  form  `|&'  rather  than
       just `|'.

       The  shell  cannot  presently  redirect  diagnostic output
       without also redirecting standard output, but `(command  >
       output-file)   >&   error-file'  is  often  an  acceptable
       workaround.   Either  output-file  or  error-file  may  be
       `/dev/tty' to send output to the terminal.

   Features
       Having  described  how  the shell accepts, parses and exe-
       cutes command lines, we now turn to a variety of its  use-
       ful features.

   Control flow
       The  shell contains a number of commands which can be used
       to regulate the flow of control in  command  files  (shell
       scripts)  and  (in  limited but useful ways) from terminal
       input.  These commands all operate by forcing the shell to
       reread  or  skip  in its input and, due to the implementa-
       tion, restrict the placement of some of the commands.

       The foreach, switch, and while statements, as well as  the
       if-then-else  form  of  the if statement, require that the
       major keywords appear in a single  simple  command  on  an
       input line as shown below.

       If the shell's input is not seekable, the shell buffers up
       input whenever a loop is being read and performs seeks  in
       this  internal  buffer to accomplish the rereading implied
       by the loop.  (To the extent that  this  allows,  backward
       gotos will succeed on non-seekable inputs.)

   Expressions
       The  if,  while  and exit builtin commands use expressions
       with a common syntax. The expressions can include  any  of
       the  operators  described in the next three sections. Note
       that the @ builtin command (q.v.)  has  its  own  separate
       syntax.

   Logical, arithmetical and comparison operators
       These  operators  are  similar  to those of C and have the
       same precedence.  They include

           ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
           <  > <<  >>  +  -  *  /  %  !  ~  (  )

       Here the precedence increases to the right, `==' `!=' `=~'
       and  `!~',  `<='  `>=' `<' and `>', `<<' and `>>', `+' and
       `-', `*' `/' and `%' being, in groups, at the same  level.
       The  `==' `!=' `=~' and `!~' operators compare their argu-
       ments as strings; all  others  operate  on  numbers.   The
       operators `=~' and `!~' are like `!=' and `==' except that
       the right hand side is a glob-pattern (see  Filename  sub-
       stitution) against which the left hand operand is matched.
       This reduces the need for use of the switch  builtin  com-
       mand  in  shell  scripts when all that is really needed is
       pattern matching.

       Strings which begin with `0' are considered octal numbers.
       Null or missing arguments are considered `0'.  The results
       of all expressions are strings,  which  represent  decimal
       numbers.   It  is important to note that no two components
       of an expression can appear in the same word; except  when
       adjacent  to components of expressions which are syntacti-
       cally significant to the parser (`&' `|' `<' `>' `('  `)')
       they should be surrounded by spaces.

   Command exit status
       Commands  can  be  executed  in expressions and their exit
       status returned by enclosing them in braces (`{}'). Remem-
       ber  that the braces should be separated from the words of
       the command by spaces. Command executions succeed, return-
       ing  true,  i.e.  `1', if the command exits with status 0,
       otherwise they fail, returning false, i.e. `0'.   If  more
       detailed  status  information is required then the command
       should be executed outside of an expression and the status
       shell variable examined.

   File inquiry operators
       Some  of these operators perform true/false tests on files
       and related objects. They are of the form -op file,  where
       op is one of

           r   Read access
           w   Write access
           x   Execute access
           X   Executable  in the path or shell builtin, e.g. `-X
               ls' and `-X ls-F'  are  generally  true,  but  `-X
               /bin/ls' is not (+)
           e   Existence
           o   Ownership
           z   Zero size
           s   Non-zero size (+)
           f   Plain file
           d   Directory
           l   Symbolic link (+) *
           b   Block special file (+)
           c   Character special file (+)
           p   Named pipe (fifo) (+) *
           S   Socket special file (+) *
           u   Set-user-ID bit is set (+)
           g   Set-group-ID bit is set (+)
           k   Sticky bit is set (+)
           t   file  (which  must  be  a  digit)  is an open file
               descriptor for a terminal device (+)
           R   Has been migrated (convex only) (+)
           L   Applies subsequent operators in a  multiple-opera-
               tor  test  to  a  symbolic link rather than to the
               file to which the link points (+) *

       file is command and filename expanded and then  tested  to
       see if it has the specified relationship to the real user.
       If file does not exist or  is  inaccessible  or,  for  the
       operators  indicated  by  `*',  if the specified file type
       does not exist on the current system, then  all  enquiries
       return false, i.e. `0'.

       These  operators  may  be  combined  for conciseness: `-xy
       file' is equivalent to `-x file && -y file'. (+) For exam-
       ple,  `-fx'  is  true  (returns  `1') for plain executable
       files, but not for directories.

       L may be used in a multiple-operator test to apply  subse-
       quent operators to a symbolic link rather than to the file
       to which the link points.  For example, `-lLo' is true for
       links  owned  by  the  invoking  user.   Lr, Lw and Lx are
       always true for links and false for  non-links.  L  has  a
       different meaning when it is the last operator in a multi-
       ple-operator test; see below.

       It is possible but not useful, and  sometimes  misleading,
       to  combine  operators which expect file to be a file with
       operators which do not, (e.g. X and t). Following L with a
       non-file   operator   can  lead  to  particularly  strange
       results.

       Other operators return other information,  i.e.  not  just
       `0'  or  `1'.  (+) They have the same format as before; op
       may be one of

           A       Last file access time, as the number  of  sec-
                   onds since the epoch
           A:      Like A, but in timestamp format, e.g. `Fri May
                   14 16:36:10 1993'
           M       Last file modification time
           M:      Like M, but in timestamp format
           C       Last inode modification time
           C:      Like C, but in timestamp format
           D       Device number
           I       Inode number
           F       Composite  file  identifier,   in   the   form
                   device:inode
           L       The  name of the file pointed to by a symbolic
                   link
           N       Number of (hard) links
           P       Permissions, in octal, without leading zero
           P:      Like P, with leading zero
           Pmode   Equivalent to `-P file  &  mode',  e.g.  `-P22
                   file'  returns  `22'  if  file  is writable by
                   group and other, `20' if by  group  only,  and
                   `0' if by neither
           Pmode:  Like Pmode:, with leading zero
           U       Numeric userid
           U:      Username,  or  the numeric userid if the user-
                   name is unknown
           G       Numeric groupid
           G:      Groupname,  or  the  numeric  groupid  if  the
                   groupname is unknown
           Z       Size, in bytes

       Only one of these operators may appear in a multiple-oper-
       ator test, and it must be the last. Note that L has a dif-
       ferent  meaning at the end of and elsewhere in a multiple-
       operator test. Because `0' is a  valid  return  value  for
       many  of these operators, they do not return `0' when they
       fail: most return `-1', and F returns `:'.

       If the shell is compiled with POSIX defined (see the  ver-
       sion  shell  variable),  the  result  of a file inquiry is
       based on the permission bits of the file and  not  on  the
       result  of the access(2) system call.  For example, if one
       tests a file with -w whose  permissions  would  ordinarily
       allow  writing but which is on a file system mounted read-
       only, the test will succeed in a POSIX shell but fail in a
       non-POSIX shell.

       File  inquiry  operators  can  also  be evaluated with the
       filetest builtin command (q.v.) (+).

   Jobs
       The shell associates a job with each pipeline.  It keeps a
       table  of  current  jobs, printed by the jobs command, and
       assigns them small integer numbers.  When a job is started
       asynchronously  with  `&',  the  shell prints a line which
       looks like

           [1] 1234

       indicating that the job which was  started  asynchronously
       was  job  number  1 and had one (top-level) process, whose
       process id was 1234.

       If you are running a job and wish to do something else you
       may hit the suspend key (usually `^Z'), which sends a STOP
       signal to the current job.  The shell will  then  normally
       indicate  that  the  job  has  been  `Suspended' and print
       another prompt.  If the listjobs shell  variable  is  set,
       all  jobs will be listed like the jobs builtin command; if
       it is set to `long' the listing will be  in  long  format,
       like  `jobs -l'.  You can then manipulate the state of the
       suspended job.  You can put it in the ``background''  with
       the  bg  command or run some other commands and eventually
       bring the job back into the ``foreground'' with fg.   (See
       also  the  run-fg-editor  editor  command.)   A `^Z' takes
       effect immediately and is like an interrupt in that  pend-
       ing  output  and  unread  input  are  discarded when it is
       typed.  The wait builtin command causes the shell to  wait
       for all background jobs to complete.

       The  `^]'  key  sends a delayed suspend signal, which does
       not generate a STOP signal until  a  program  attempts  to
       read(2)  it,  to  the  current  job.  This can usefully be
       typed ahead when you have prepared some commands for a job
       which  you  wish to stop after it has read them.  The `^Y'
       key performs this function in csh(1); in tcsh, `^Y' is  an
       editing command. (+)

       A  job  being  run  in the background stops if it tries to
       read from the  terminal.   Background  jobs  are  normally
       allowed  to  produce  output,  but this can be disabled by
       giving the command `stty tostop'.  If  you  set  this  tty
       option,  then  background  jobs will stop when they try to
       produce output like they do when they try to read input.

       There are several ways to refer to jobs in the shell.  The
       character `%' introduces a job name.  If you wish to refer
       to job number 1, you can name it as `%1'.  Just  naming  a
       job  brings  it  to the foreground; thus `%1' is a synonym
       for `fg %1', bringing job  1  back  into  the  foreground.
       Similarly,  saying `%1 &' resumes job 1 in the background,
       just like `bg %1'. A job can also be  named  by  an  unam-
       bigous  prefix  of  the string typed in to start it: `%ex'
       would normally restart a suspended  ex(1)  job,  if  there
       were  only  one  suspended  job  whose name began with the
       string `ex'.  It is also possible  to  say  `%?string'  to
       specify a job whose text contains string, if there is only
       one such job.

       The shell maintains a notion of the current  and  previous
       jobs.   In  output  pertaining to jobs, the current job is
       marked with a `+' and the previous job with  a  `-'.   The
       abbreviations  `%+',  `%', and (by analogy with the syntax
       of the history mechanism) `%%' all refer  to  the  current
       job, and `%-' refers to the previous job.

       The job control mechanism requires that the stty(1) option
       `new' be set on some systems.  It is an  artifact  from  a
       `new' implementation of the tty driver which allows gener-
       ation of interrupt characters from the  keyboard  to  tell
       jobs  to  stop.  See stty(1) and the setty builtin command
       for details on setting options in the new tty driver.

   Status reporting
       The shell learns immediately whenever  a  process  changes
       state.   It  normally  informs  you whenever a job becomes
       blocked so that no further progress is possible, but  only
       just  before  it prints a prompt.  This is done so that it
       does not otherwise disturb your work.   If,  however,  you
       set  the  shell variable notify, the shell will notify you
       immediately of  changes  of  status  in  background  jobs.
       There  is also a shell command notify which marks a single
       process so that its status  changes  will  be  immediately
       reported.   By  default  notify marks the current process;
       simply say `notify' after starting  a  background  job  to
       mark it.

       When  you  try  to leave the shell while jobs are stopped,
       you will be warned that `You have stopped jobs.'  You  may
       use the jobs command to see what they are.  If you do this
       or immediately try to exit again, the shell will not  warn
       you  a  second time, and the suspended jobs will be termi-
       nated.

   Automatic, periodic and timed events (+)
       There are various ways to  run  commands  and  take  other
       actions  automatically  at  various  times  in  the ``life
       cycle'' of  the  shell.  They  are  summarized  here,  and
       described  in  detail  under  the appropriate Builtin com-
       mands, Special shell variables and Special aliases.

       The sched builtin command puts commands  in  a  scheduled-
       event list, to be executed by the shell at a given time.

       The  beepcmd,  cwdcmd, periodic and precmd Special aliases
       can be set, respectively, to  execute  commands  when  the
       shell  wants  to ring the bell, when the working directory
       changes, every tperiod minutes and before each prompt.

       The autologout shell variable can be set  to  log  out  or
       lock the shell after a given number of minutes of inactiv-
       ity.

       The mail shell variable can be set to check for  new  mail
       periodically.

       The  printexitvalue shell variable can be set to print the
       exit status of commands which exit  with  a  status  other
       than zero.

       The rmstar shell variable can be set to ask the user, when
       `rm *' is typed, if that is really what was meant.

       The time shell variable can be set  to  execute  the  time
       builtin  command  after the completion of any process that
       takes more than a given number of CPU seconds.

       The watch and who shell variables can  be  set  to  report
       when  selected  users  log  in or out, and the log builtin
       command reports on those users at any time.

   Native Language System support (+)
       The shell is eight bit clean (if so compiled; see the ver-
       sion  shell  variable)  and  thus  supports character sets
       needing this capability.  NLS support differs depending on
       whether  or not the shell was compiled to use the system's
       NLS (again, see version).  In either case, 7-bit ASCII  is
       the default for character classification (e.g. which char-
       acters are printable) and sorting, and changing  the  LANG
       or  LC_CTYPE environment variables causes a check for pos-
       sible changes in these respects.

       When using the system's NLS, the setlocale(3) function  is
       called  to  determine appropriate character classification
       and sorting.  This function typically  examines  the  LANG
       and  LC_CTYPE  environment  variables; refer to the system
       documentation for further details.   When  not  using  the
       system's  NLS, the shell simulates it by assuming that the
       ISO 8859-1 character set is used whenever  either  of  the
       LANG  and  LC_CTYPE variables are set, regardless of their
       values. Sorting is not affected for the simulated NLS.

       In addition, with both real and simulated NLS, all  print-
       able  characters  in  the range \200-\377, i.e. those that
       have M-char bindings, are automatically rebound  to  self-
       insert-command.  The corresponding binding for the escape-
       char sequence, if any, is left  alone.   These  characters
       are  not  rebound  if the NOREBIND environment variable is
       set. This may be useful for the simulated NLS or a  primi-
       tive  real  NLS  which assumes full ISO 8859-1. Otherwise,
       all M-char bindings in the range \240-\377 are effectively
       undone.  Explicitly rebinding the relevant keys with bind-
       key is of course still possible.

       Unknown characters (i.e. those that are neither  printable
       nor  control  characters)  are printed in the format \nnn.
       If the tty is not in 8 bit mode, other  8  bit  characters
       are printed by converting them to ASCII and using standout
       mode. The shell never changes the 7/8 bit mode of the  tty
       and  tracks  user-initiated  changes  of 7/8 bit mode. NLS
       users (or, for that matter, those who want to use  a  meta
       key)  may  need  to  explicitly  set the tty in 8 bit mode
       through the appropriate  stty(1)  command  in,  e.g.,  the
       ~/.login file.

   OS variant support (+)
       A  number  of new builtin commands are provided to support
       features  in  particular  operating   systems.   All   are
       described in detail in the Builtin commands section.

       On   systems   that  support  TCF  (aix-ibm370,  aix-ps2),
       getspath and setspath get and  set  the  system  execution
       path,  getxvers  and setxvers get and set the experimental
       version prefix  and  migrate  migrates  processes  between
       sites.  The jobs builtin prints the site on which each job
       is executing.

       Under Domain/OS, inlib adds shared libraries to  the  cur-
       rent  environment,  rootnode  changes the rootnode and ver
       changes the systype.

       Under Mach, setpath is equivalent to Mach's setpath(1).

       Under Masscomp/RTU and Harris  CX/UX,  universe  sets  the
       universe.

       Under  Harris  CX/UX,  ucb or att runs a command under the
       specified universe.

       Under Convex/OS, warp prints or sets the universe.

       The VENDOR,  OSTYPE  and  MACHTYPE  environment  variables
       indicate  respectively  the  vendor,  operating system and
       machine type (microprocessor class or  machine  model)  of
       the system on which the shell thinks it is running.  These
       are particularly useful when sharing one's home  directory
       between several types of machines; one can, for example,

           set  path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

       in one's ~/.login and put executables  compiled  for  each
       machine in the appropriate directory.

       The  version  shell  variable  indicates what options were
       chosen when the shell was compiled.

       Note also the newgrp builtin, the afsuser  and  echo_style
       shell  variables and the system-dependent locations of the
       shell's input files (see FILES).

   Signal handling
       Login shells  ignore  interrupts  when  reading  the  file
       ~/.logout.   The shell ignores quit signals unless started
       with -q.  Login shells catch  the  terminate  signal,  but
       non-login shells inherit the terminate behavior from their
       parents.  Other signals have the values  which  the  shell
       inherited from its parent.

       In  shell  scripts,  the shell's handling of interrupt and
       terminate signals can be controlled with onintr,  and  its
       handling  of hangups can be controlled with hup and nohup.

       The shell exits on a hangup (see  also  the  logout  shell
       variable).   By  default, the shell's children do too, but
       the shell does not send them a hangup when it exits.   hup
       arranges for the shell to send a hangup to a child when it
       exits, and nohup sets a child to ignore hangups.

   Terminal management (+)
       The shell uses three different sets of terminal  (``tty'')
       modes: `edit', used when editing, `quote', used when quot-
       ing literal characters, and `execute', used when executing
       commands.  The shell holds some settings in each mode con-
       stant, so commands which leave the tty in a confused state
       do  not  interfere with the shell.  The shell also matches
       changes in the speed and padding of the tty.  The list  of
       tty modes that are kept constant can be examined and modi-
       fied with the setty builtin.  Note that although the  edi-
       tor  uses CBREAK mode (or its equivalent), it takes typed-
       ahead characters anyway.

       The echotc, settc and  telltc  commands  can  be  used  to
       manipulate  and  debug terminal capabilities from the com-
       mand line.

       On systems that support SIGWINCH or SIGWINDOW,  the  shell
       adapts  to  window  resizing automatically and adjusts the
       environment variables LINES and COLUMNS  if  set.  If  the
       environment  variable TERMCAP contains li# and co# fields,
       the shell adjusts them to reflect the new window size.

REFERENCE
       The next sections of  this  manual  describe  all  of  the
       available  Builtin  commands,  Special aliases and Special
       shell variables.

   Builtin commands
       %job    A synonym for the fg builtin command.

       %job &  A synonym for the bg builtin command.

       :       Does nothing, successfully.

       @
       @ name = expr
       @ name[index] = expr
       @ name++|--
       @ name[index]++|--
               The first form prints  the  values  of  all  shell
               variables.

               The second form assigns the value of expr to name.
               The third form assigns the value of  expr  to  the
               index'th  component  of  name;  both  name and its
               index'th component must already exist.

               expr may contain the operators `*', `+',  etc.  as
               in  C.   If expr contains `<', `>', `&' or `' then
               at least that part of expr must be  placed  within
               `()'.  Note that the syntax of expr has nothing to
               do with that described under Expressions.

               The fourth and fifth  forms  increment  (`++')  or
               decrement (`--') name or its index'th component.

               The  space  between `@' and name is required.  The
               spaces between name and `=' and  between  `='  and
               expr  are  optional.   Components  of expr must be
               separated by spaces.

       alias [name [wordlist]]
               Without arguments, prints all aliases.  With name,
               prints   the   alias  for  name.   With  name  and
               wordlist, assigns wordlist as the alias  of  name.
               wordlist  is  command  and  filename  substituted.
               name may not be `alias' or  `unalias'.   See  also
               the unalias builtin command.

       alloc   Shows  the amount of dynamic memory acquired, bro-
               ken down into used and free memory.  With an argu-
               ment  shows  the number of free and used blocks in
               each size category.  The categories start at  size
               8  and double at each step.  This command's output
               may vary across system types, since systems  other
               than the VAX may use a different memory allocator.

       bg [%job ...]
               Puts the specified jobs  (or,  without  arguments,
               the  current  job) into the background, continuing
               each if it is stopped.  job may  be  a  number,  a
               string,  `',  `%',  `+'  or `-' as described under
               Jobs.

       bindkey [-l|-d|-e|-v|-u] (+)
       bindkey [-a] [-b] [-k] [-r] [--] key (+)
       bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
               Without options, the first form  lists  all  bound
               keys  and  the  editor  command  to  which each is
               bound, the second form lists the editor command to
               which  key  is  bound and the third form binds the
               editor command command to key.  Options include:

               -l  Lists all editor commands and a short descrip-
                   tion of each.
               -d  Binds  all  keys  to the standard bindings for
                   the default editor.
               -e  Binds all keys to the standard GNU  Emacs-like
                   bindings.
               -v  Binds  all  keys  to  the  standard vi(1)-like
                   bindings.
               -a  Lists or changes key-bindings in the  alterna-
                   tive  key map.  This is the key map used in vi
                   command mode.
               -b  key is  interpreted  as  a  control  character
                   written  ^character (e.g. `^A') or C-character
                   (e.g. `C-A'), a meta character written M-char-
                   acter  (e.g. `M-A'), a function key written F-
                   string (e.g. `F-string'), or an extended  pre-
                   fix key written X-character (e.g. `X-A').
               -k  key  is  interpreted  as  a symbolic arrow key
                   name, which may be one of `down', `up', `left'
                   or `right'.
               -r  Removes  key's  binding.  Be careful: `bindkey
                   -r' does not bind key  to  self-insert-command
                   (q.v.), it unbinds key completely.
               -c  command  is interpreted as a builtin or exter-
                   nal command instead of an editor command.
               -s  command is  taken  as  a  literal  string  and
                   treated  as  terminal input when key is typed.
                   Bound keys in command are themselves  reinter-
                   preted,  and  this continues for ten levels of
                   interpretation.
               --  Forces a break from option processing, so  the
                   next  word  is  taken as key even if it begins
                   with '-'.
               -u (or any invalid option)
                   Prints a usage message.

               key may be a single character or a string.   If  a
               command  is bound to a string, the first character
               of the string is bound to sequence-lead-in and the
               entire string is bound to the command.

               Control characters in key can be literal (they can
               be typed by preceding them with the editor command
               quoted-insert,  normally bound to `^V') or written
               caret-character style, e.g. `^A'. Delete is  writ-
               ten  `^?'  (caret-question mark).  key and command
               can contain backslashed escape sequences  (in  the
               style of System V echo(1)) as follows:

                   \a      Bell
                   \b      Backspace
                   \e      Escape
                   \f      Form feed
                   \n      Newline
                   \r      Carriage return
                   \t      Horizontal tab
                   \v      Vertical tab
                   \nnn    The  ASCII  character corresponding to
                           the octal number nnn

               `\' nullifies the special meaning of the following
               character, if it has any, notably `\' and `^'.

       break   Causes  execution  to  resume after the end of the
               nearest enclosing foreach or while. The  remaining
               commands on the current line are executed.  Multi-
               level breaks are thus possible by writing them all
               on one line.

       breaksw Causes  a  break from a switch, resuming after the
               endsw.

       builtins (+)
               Prints the names of all builtin commands.

       bye (+) A synonym for the logout builtin command.   Avail-
               able  only  if  the shell was so compiled; see the
               version shell variable.

       case label:
               A label in a switch statement as discussed  below.

       cd [-p] [-l] [-n|-v] [name]
               If  a directory name is given, changes the shell's
               working directory to  name.  If  not,  changes  to
               home.   If  name  is  `-' it is interpreted as the
               previous working directory  (see  Other  substitu-
               tions).  (+)  If name is not a subdirectory of the
               current directory (and does not  begin  with  `/',
               `./'  or  `../'),  each  component of the variable
               cdpath is checked to see if it has a  subdirectory
               name.  Finally,  if  all  else fails but name is a
               shell variable whose value begins with  `/',  then
               this is tried to see if it is a directory.

               With  -p,  prints  the final directory stack, just
               like dirs.  The -l, -n and -v flags have the  same
               effect on cd as on dirs, and they imply -p. (+)

               See also the implicitcd shell variable.

       chdir   A synonym for the cd builtin command.

       complete  [command
               [word/pattern/list[:select]/[[suffix]/] ...]] (+)
               Without  arguments,  lists  all completions.  With
               command, lists completions for command.  With com-
               mand and word etc., defines completions.

               command  may be a full command name or a glob-pat-
               tern (see Filename  substitution).  It  can  begin
               with  `-'  to  indicate  that completion should be
               used only when command is ambiguous.

               word specifies which word relative to the  current
               word  is  to  be  completed, and may be one of the
               following:

                   c   Current-word  completion.   pattern  is  a
                       glob-pattern  which  must match the begin-
                       ning of the current word  on  the  command
                       line.  pattern  is ignored when completing
                       the current word.
                   C   Like c, but includes pattern when complet-
                       ing the current word.
                   n   Next-word  completion.  pattern is a glob-
                       pattern which must match the beginning  of
                       the previous word on the command line.
                   N   Like  n,  but  must match the beginning of
                       the word two before the current word.
                   p   Position-dependent completion.  pattern is
                       a numeric range, with the same syntax used
                       to  index  shell  variables,  which   must
                       include the current word.

               list, the list of possible completions, may be one
               of the following:

                   a       Aliases
                   b       Bindings (editor commands)
                   c       Commands  (builtin  or  external  com-
                           mands)
                   C       External commands which begin with the
                           supplied path prefix
                   d       Directories
                   D       Directories which begin with the  sup-
                           plied path prefix
                   e       Environment variables
                   f       Filenames
                   F       Filenames  which  begin  with the sup-
                           plied path prefix
                   g       Groupnames
                   j       Jobs
                   l       Limits
                   n       Nothing
                   s       Shell variables
                   S       Signals
                   t       Plain (``text'') files
                   T       Plain  (``text'')  files  which  begin
                           with the supplied path prefix
                   v       Any variables
                   u       Usernames
                   x       Like  n,  but prints select when list-
                           choices is used.
                   X       Completions
                   $var    Words from the variable var
                   (...)   Words from the given list
                   `...`   Words from the output of command

               select is an  optional  glob-pattern.   If  given,
               only  words  from list which match select are con-
               sidered and the fignore shell variable is ignored.
               The  last three types of completion may not have a
               select pattern, and x uses select as  an  explana-
               tory  message when the list-choices editor command
               is used.

               suffix is a single character to be appended  to  a
               successful  completion.   If null, no character is
               appended. If omitted (in  which  case  the  fourth
               delimiter   can  also  be  omitted),  a  slash  is
               appended to  directories  and  a  space  to  other
               words.

               Now  for  some  examples.  Some commands take only
               directories as arguments, so there's no point com-
               pleting plain files.

                   > complete cd 'p/1/d/'

               completes  only  the  first  word  following  `cd'
               (`p/1') with a directory.  p-type  completion  can
               also be used to narrow down command completion:

                   > co[^D]
                   complete compress
                   > complete -co* 'p/0/(compress)/'
                   > co[^D]
                   > compress

               This completion completes commands (words in posi-
               tion 0, `p/0') which begin with `co' (thus  match-
               ing  `co*')  to  `compress'  (the only word in the
               list).  The leading `-' indicates that  this  com-
               pletion  is  to  be  used only with ambiguous com-
               mands.

                   > complete find 'n/-user/u/'

               is an example of n-type completion. Any word  fol-
               lowing `find' and immediately following `-user' is
               completed from the list of users.

                   > complete cc 'c/-I/d/'

               demonstrates c-type completion. Any word following
               `cc'  and  beginning  with  `-I' is completed as a
               directory. `-I' is not taken as part of the direc-
               tory because we used lowercase c.

               Different  lists  are  useful  with different com-
               mands.

                   > complete alias 'p/1/a/'
                   > complete man 'p/*/c/'
                   > complete set 'p/1/s/'
                   > complete true 'p/1/x:Truth has no options./'

               These   complete   words  following  `alias'  with
               aliases, `man' with commands, and `set' with shell
               variables.   `true' doesn't have any options, so x
               does nothing  when  completion  is  attempted  and
               prints  `Truth  has  no  options.' when completion
               choices are listed.

               Note that the man example, and several other exam-
               ples  below, could just as well have used 'c/*' or
               'n/*' as 'p/*'.

               Words can be completed from a  variable  evaluated
               at completion time,

                   > complete ftp 'p/1/$hostnames/'
                   >  set hostnames = (rtfm.mit.edu tesla.ee.cor-
                   nell.edu)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu
                   > ftp [^C]
                   > set hostnames = (rtfm.mit.edu  tesla.ee.cor-
                   nell.edu uunet.uu.net)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net

               or from a command run at completion time:

                   >  complete  kill  'p/*/`ps  |  awk   \{print\
                   \$1\}`/'
                   > kill -9 [^D]
                   23113 23377 23380 23406 23429 23529 23530 PID

               Note  that  the  complete  command does not itself
               quote its arguments, so the braces, space and  `$'
               in `{print $1}' must be quoted explicitly.

               One command can have multiple completions:

                   > complete dbx 'p/2/(core)/' 'p/*/c/'

               completes  the  second  argument to `dbx' with the
               word `core' and all other arguments with commands.
               Note  that  the positional completion is specified
               before the next-word  completion.   Since  comple-
               tions  are  evaluated  from  left to right, if the
               next-word completion were specified first it would
               always  match  and the positional completion would
               never be executed. This is a common  mistake  when
               defining a completion.

               The  select pattern is useful when a command takes
               only files with particular forms as arguments. For
               example,

                   > complete cc 'p/*/f:*.[cao]/'

               completes  `cc'  arguments only to files ending in
               `.c', `.a', or  `.o'.   select  can  also  exclude
               files,   using   negation  of  a  glob-pattern  as
               described under Filename substitution.  One  might
               use

                   >                  complete                 rm
                   'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'

               to exclude precious source code from `rm'  comple-
               tion.  Of  course,  one  could still type excluded
               names manually or override the  completion  mecha-
               nism  using the complete-word-raw or list-choices-
               raw editor commands (q.v.).

               The `C', `D', `F' and `T' lists are like `c', `d',
               `f'  and `t' respectively, but they use the select
               argument in a different way: to  restrict  comple-
               tion  to  files  beginning  with a particular path
               prefix. For example, the Elm mail program uses `='
               as  an  abbreviation for one's mail directory. One
               might use

                   > complete elm c@=@F:$HOME/Mail/@

               to complete `elm -f ='  as  if  it  were  `elm  -f
               ~/Mail/'.  Note that we used `@' instead of `/' to
               avoid confusion with the select argument,  and  we
               used `$HOME' instead of `~' because home directory
               substitution only works  at  the  beginning  of  a
               word.

               suffix  is  used  to add a nonstandard suffix (not
               space or `/' for directories) to completed  words.

                   > complete finger 'c/*@/$hostnames/' 'p/1/u/@'

               completes arguments to `finger' from the  list  of
               users,  appends  an  `@', and then completes after
               the `@' from the `hostnames' variable. Note  again
               the  order in which the completions are specified.

               Finally, here's a complex example for inspiration:

                   > complete find \
                   'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
                   'n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
                   'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
                   'n/-type/(b c d f l p s)/' \
                   'c/-/(name newer cpio ncpio exec ok user \
                   group fstype type atime ctime depth inum \
                   ls mtime nogroup nouser perm print prune \
                   size xdev)/' \
                   'p/*/d/'

               This  completes words following `-name', `-newer',
               `-cpio' or `ncpio' (note the pattern which matches
               both)  to  files, words following `-exec' or `-ok'
               to commands, words following `user' and `group' to
               users  and groups respectively and words following
               `-fstype' or  `-type'  to  members  of  the  given
               lists.  It  also completes the switches themselves
               from the given list (note the use of  c-type  com-
               pletion) and completes anything not otherwise com-
               pleted to a directory. Whew.

               Remember that programmed completions  are  ignored
               if  the  word being completed is a tilde substitu-
               tion (beginning with `~') or a variable (beginning
               with  `$').   complete is an experimental feature,
               and the syntax may change in  future  versions  of
               the  shell.   See also the uncomplete builtin com-
               mand.

       continue
               Continues execution of the nearest enclosing while
               or  foreach.  The rest of the commands on the cur-
               rent line are executed.

       default:
               Labels the default case in a switch statement.  It
               should come after all case labels.

       dirs [-l] [-n|-v]
       dirs -S|-L [filename] (+)
       dirs -c (+)
               The first form prints the directory stack. The top
               of the stack is at the left and the  first  direc-
               tory  in the stack is the current directory.  With
               -l, `~' or  `~name'  in  the  output  is  expanded
               explicitly  to  home  or  the pathname of the home
               directory for user name. (+) With -n, entries  are
               wrapped  before they reach the edge of the screen.
               (+) With -v, entries are  printed  one  per  line,
               preceded by their stack postions. (+) If more than
               one of -n or -v is given, -v takes precedence.  -p
               is accepted but does nothing.

               With -S, the second form saves the directory stack
               to filename as a series of cd and pushd  commands.
               With -L, the shell sources filename, which is pre-
               sumably a directory stack file  saved  by  the  -S
               option or the savedirs mechanism.  In either case,
               dirsfile is used if  filename  is  not  given  and
               ~/.cshdirs is used if dirsfile is unset.

               Note  that login shells do the equivalent of `dirs
               -L' on startup and, if savedirs is set, `dirs  -S'
               before  exiting.   Because  only ~/.tcshrc is nor-
               mally sourced before ~/.cshdirs,  dirsfile  should
               be set in ~/.tcshrc rather than ~/.login.

               The last form clears the directory stack.

       echo [-n] word ...
               Writes  each  word to the shell's standard output,
               separated by spaces and terminated with a newline.
               The  echo_style  shell variable may be set to emu-
               late (or not) the flags and  escape  sequences  of
               the  BSD  and/or  System  V  versions of echo; see
               echo(1).

       echotc [-sv] arg ... (+)
               Exercises the  terminal  capabilities  (see  term-
               cap(5)) in args.  For example, 'echotc home' sends
               the cursor to the home position, 'echotc cm 3  10'
               sends it to column 3 and row 10, and 'echotc ts 0;
               echo "This is a test."; echotc fs' prints "This is
               a test."  in the status line.

               If  arg  is  'baud',  'cols',  'lines',  'meta' or
               'tabs', prints the value of that capability ("yes"
               or  "no" indicating that the terminal does or does
               not have that capability). One might use  this  to
               make  the  output from a shell script less verbose
               on slow terminals, or limit command output to  the
               number of lines on the screen:

                   > set history=`echotc lines`
                   > @ history--

               Termcap  strings  may contain wildcards which will
               not echo correctly.  One should use double  quotes
               when  setting a shell variable to a terminal capa-
               bility string, as in the  following  example  that
               places the date in the status line:

                   > set tosl="`echotc ts 0`"
                   > set frsl="`echotc fs`"
                   > echo -n "$tosl";date; echo -n "$frsl"

               With -s, nonexistent capabilities return the empty
               string rather than causing  an  error.   With  -v,
               messages are verbose.

       else
       end
       endif
       endsw   See  the  description  of the foreach, if, switch,
               and while statements below.

       eval arg ...
               Treats the arguments as input  to  the  shell  and
               executes  the  resulting command(s) in the context
               of the current shell. This is usually used to exe-
               cute  commands  generated as the result of command
               or variable  substitution,  since  parsing  occurs
               before  these  substitutions.   See  tset(1) for a
               sample use of eval.

       exec command
               Executes the specified command  in  place  of  the
               current shell.

       exit [expr]
               The shell exits either with the value of the spec-
               ified expr  (an  expression,  as  described  under
               Expressions)  or,  without expr, with the value of
               the status variable.

       fg [%job ...]
               Brings the specified jobs (or, without  arguments,
               the  current  job) into the foreground, continuing
               each if it is stopped.  job may  be  a  number,  a
               string,  `',  `%',  `+'  or `-' as described under
               Jobs.  See also the run-fg-editor editor  command.

       filetest -op file ... (+)
               Applies  op  (which  is a file inquiry operator as
               described under File inquiry  operators)  to  each
               file  and returns the results as a space-separated
               list.

       foreach name (wordlist)
       ...
       end     Successively sets the variable name to each member
               of  wordlist and executes the sequence of commands
               between this command and the matching end.   (Both
               foreach  and  end  must  appear  alone on separate
               lines.)  The builtin command continue may be  used
               to  continue  the loop prematurely and the builtin
               command break to terminate it  prematurely.   When
               this  command  is read from the terminal, the loop
               is  read  once  prompting  with  `foreach?  '  (or
               prompt2)  before  any  statements  in the loop are
               executed.  If you make a mistake typing in a  loop
               at the terminal you can rub it out.

       getspath (+)
               Prints the system execution path. (TCF only)

       getxvers (+)
               Prints the experimental version prefix. (TCF only)

       glob wordlist
               Like echo, but no `\' escapes are  recognized  and
               words are delimited by null characters in the out-
               put.  Useful for programs which wish  to  use  the
               shell to filename expand a list of words.

       goto word
               word  is filename and command-substituted to yield
               a string of the form `label'.  The  shell  rewinds
               its input as much as possible, searches for a line
               of the form `label:', possibly preceded by  blanks
               or  tabs, and continues execution after that line.

       hashstat
               Prints a statistics line indicating how  effective
               the  internal hash table has been at locating com-
               mands (and avoiding exec's). An exec is  attempted
               for  each  component  of  the  path where the hash
               function indicates a possible  hit,  and  in  each
               component which does not begin with a `/'.

               On machines without vfork(2), prints only the num-
               ber and size of hash buckets.

       history [-hTr] [n]
       history -S|-L|-M [filename] (+)
       history -c (+)
               The first form prints the history event list.   If
               n  is  given  only  the  n  most recent events are
               printed or saved.  With -h, the  history  list  is
               printed  without  leading numbers. If -T is speci-
               fied, timestamps are printed also in comment form.
               (This  can  be  used to produce files suitable for
               loading with 'history -L' or 'source  -h'.)   With
               -r,  the  order  of  printing is most recent first
               rather than oldest first.

               With -S, the second form saves the history list to
               filename.  If the first word of the savehist shell
               variable is set to a number,  at  most  that  many
               lines  are  saved.  If the second word of savehist
               is set to `merge', the history list is merged with
               the  existing history file instead of replacing it
               (if there is one) and sorted by  time  stamp.  (+)
               Merging  is intended for an environment like the X
               Window System with several shells in  simultaneous
               use.   Currently  it only succeeds when the shells
               quit nicely one after another.

               With -L, the shell appends filename, which is pre-
               sumably  a  history list saved by the -S option or
               the savehist mechanism, to the history  list.   -M
               is  like  -L,  but  the  contents  of filename are
               merged into the history list and sorted by  times-
               tamp.   In  either case, histfile is used if file-
               name is not given and ~/.history is used if  hist-
               file  is  unset.   `history  -L'  is  exactly like
               'source -h' except that  it  does  not  require  a
               filename.

               Note  that login shells do the equivalent of `his-
               tory -L' on startup and, if savehist is set, `his-
               tory  -S'  before exiting.  Because only ~/.tcshrc
               is normally sourced  before  ~/.history,  histfile
               should be set in ~/.tcshrc rather than ~/.login.

               If  histlit  is  set,  the  first and second forms
               print and save the literal  (unexpanded)  form  of
               the history list.

               The last form clears the history list.

       hup [command] (+)
               With  command, runs command such that it will exit
               on a hangup signal and arranges for the  shell  to
               send  it  a  hangup  signal  when the shell exits.
               Note that commands may set their own  response  to
               hangups,  overriding  hup.   Without  an  argument
               (allowed only in a shell script), causes the shell
               to  exit  on  a  hangup  for  the remainder of the
               script.  See also Signal handling  and  the  nohup
               builtin command.

       if (expr) command
               If expr (an expression, as described under Expres-
               sions) evaluates true, then command  is  executed.
               Variable substitution on command happens early, at
               the same time it does for the rest of the if  com-
               mand.   command  must  be a simple command, not an
               alias, a pipeline, a command list or  a  parenthe-
               sized  command  list,  but  it may have arguments.
               Input/output redirection occurs even  if  expr  is
               false  and command is thus not executed; this is a
               bug.

       if (expr) then
       ...
       else if (expr2) then
       ...
       else
       ...
       endif   If the specified expr is true then the commands to
               the first else are executed; otherwise if expr2 is
               true then the commands to the second else are exe-
               cuted,  etc.  Any number of else-if pairs are pos-
               sible; only one endif is needed.  The else part is
               likewise optional.  (The words else and endif must
               appear at the beginning of  input  lines;  the  if
               must  appear  alone  on its input line or after an
               else.)

       inlib shared-library ... (+)
               Adds each shared-library to the  current  environ-
               ment.  There is no way to remove a shared library.
               (Domain/OS only)

       jobs [-l]
               Lists the active jobs. With -l, lists process  IDs
               in addition to the normal information. On TCF sys-
               tems, prints the site on which each job is execut-
               ing.

       kill [-signal] %job|pid ...
       kill -l The  first form sends the specified signal (or, if
               none is given, the TERM (terminate) signal) to the
               specified jobs or processes.  job may be a number,
               a string, `', `%', `+' or `-' as  described  under
               Jobs.   Signals  are  either given by number or by
               name (as given in /usr/include/signal.h,  stripped
               of  the  prefix  `SIG').  There is no default job;
               saying just `kill' does not send a signal  to  the
               current  job.   If  the  signal being sent is TERM
               (terminate) or HUP (hangup), then the job or  pro-
               cess  is  sent  a  CONT (continue) signal as well.
               The second form lists the signal names.

       limit [-h] [resource [maximum-use]]
               Limits the consumption by the current process  and
               each process it creates to not individually exceed
               maximum-use on the specified resource. If no maxi-
               mum-use  is  given,  then  the  current  limit  is
               printed; if no resource is given, then all limita-
               tions  are  given.   If  the -h flag is given, the
               hard limits are used instead of the  current  lim-
               its.  The hard limits impose a ceiling on the val-
               ues of the current limits.   Only  the  super-user
               may raise the hard limits, but a user may lower or
               raise the current limits within the legal range.

               Controllable resources currently  include  cputime
               (the  maximum  number of cpu-seconds to be used by
               each process), filesize (the largest  single  file
               which  can  be  created),  datasize  (the  maximum
               growth of the data+stack region via sbrk(2) beyond
               the end of the program text), stacksize (the maxi-
               mum  size  of  the  automatically-extended   stack
               region),  coredumpsize  (the  size  of the largest
               core dump that will be  created),  and  memoryuse,
               the  maximum  amount  of physical memory a process
               may have allocated to it at a given time.

               maximum-use may be given as a (floating  point  or
               integer)  number  followed by a scale factor.  For
               all limits other than cputime the default scale is
               `k' or `kilobytes' (1024 bytes); a scale factor of
               `m' or `megabytes' may also be used.  For  cputime
               the  default  scaling  is `seconds', while `m' for
               minutes or `h' for hours, or a time  of  the  form
               `mm:ss' giving minutes and seconds may be used.

               For  both  resource names and scale factors, unam-
               biguous prefixes of the names suffice.

       log (+) Prints the watch shell  variable  and  reports  on
               each  user  indicated  in  watch who is logged in,
               regardless of when they last logged in.  See  also
               watchlog.

       login   Terminates  a  login  shell,  replacing it with an
               instance of /bin/login. This is  one  way  to  log
               off, included for compatibility with sh(1).

       logout  Terminates  a  login  shell.  Especially useful if
               ignoreeof is set.

       ls-F [-switch ...] [file ...] (+)
               Lists files like `ls  -F',  but  much  faster.  It
               identifies  each type of special file in the list-
               ing with a special character:

               /   Directory
               *   Executable
               #   Block device
               %   Character device
               |   Named pipe (systems with named pipes only)
               =   Socket (systems with sockets only)
               @   Symbolic link  (systems  with  symbolic  links
                   only)
               +   Hidden  directory (AIX only) or context depen-
                   dent (HP/UX only)
               :   Network special (HP/UX only)

               If the listlinks shell variable is  set,  symbolic
               links  are  identified  in  more  detail (only, of
               course, on systems which have them):

               @   Symbolic link to a non-directory
               >   Symbolic link to a directory
               &   Symbolic link to nowhere

               listlinks also slows down ls-F and  causes  parti-
               tions  holding  files pointed to by symbolic links
               to be mounted.

               If the listflags shell variable is set to `x', `a'
               or  `A',  or  any combination thereof (e.g. `xA'),
               they are used as flags to ls-F, making it act like
               `ls  -xF',  `ls  -Fa',  `ls  -FA' or a combination
               (e.g. `ls -FxA').  On machines where  `ls  -C'  is
               not  the  default, ls-F acts like `ls -CF', unless
               listflags contains an `x', in which case  it  acts
               like `ls -xF'.  ls-F passes its arguments to ls(1)
               if it is given any switches, so  `alias  ls  ls-F'
               generally does the right thing.

               The  ls-F  builtin  can list files using different
               colors depending on the filetype or extension. See
               the color tcsh variable and the LS_COLORS environ-
               ment variable.

       migrate [-site] pid|%jobid ... (+)
       migrate -site (+)
               The first form migrates the process or job to  the
               site  specified  or the default site determined by
               the system path.  The second form is equivalent to
               `migrate  -site  $$': it migrates the current pro-
               cess to the specified site.  Migrating  the  shell
               itself  can  cause  unexpected behavior, since the
               shell does not like to lose its tty. (TCF only)

       newgrp [-] group (+)
               Equivalent  to  `exec  newgrp';   see   newgrp(1).
               Available  only  if the shell was so compiled; see
               the version shell variable.

       nice [+number] [command]
               Sets the scheduling priority for the shell to num-
               ber,  or, without number, to 4. With command, runs
               command at the appropriate priority.  The  greater
               the  number,  the  less cpu the process gets.  The
               super-user may specify negative priority by  using
               `nice -number ...'.  Command is always executed in
               a sub-shell, and the restrictions placed  on  com-
               mands in simple if statements apply.

       nohup [command]
               With  command,  runs  command  such  that  it will
               ignore hangup signals.  Note that commands may set
               their  own  response to hangups, overriding nohup.
               Without an  argument  (allowed  only  in  a  shell
               script),  causes  the  shell to ignore hangups for
               the remainder of the script.  See also Signal han-
               dling and the hup builtin command.

       notify [%job ...]
               Causes the shell to notify the user asynchronously
               when the status of any of the specified jobs  (or,
               without %job, the current job) changes, instead of
               waiting until the next prompt as  is  usual.   job
               may  be a number, a string, `', `%', `+' or `-' as
               described under Jobs.  See also the  notify  shell
               variable.

       onintr [-|label]
               Controls  the  action  of the shell on interrupts.
               Without arguments, restores the default action  of
               the  shell  on  interrupts,  which is to terminate
               shell scripts or to return to the terminal command
               input  level.   With `-', causes all interrupts to
               be ignored.  With label, causes the shell to  exe-
               cute  a `goto label' when an interrupt is received
               or a  child  process  terminates  because  it  was
               interrupted.

               onintr is ignored if the shell is running detached
               and in system startup  files  (see  FILES),  where
               interrupts are disabled anyway.

       popd [-p] [-l] [-n|-v] [+n]
               Without  arguments,  pops  the directory stack and
               returns to the new top directory.  With  a  number
               `+n', discards the n'th entry in the stack.

               Finally,  all forms of popd print the final direc-
               tory stack, just like dirs. The pushdsilent  shell
               variable  can  be  set  to prevent this and the -p
               flag can be given to  override  pushdsilent.   The
               -l,  -n  and -v flags have the same effect on popd
               as on dirs. (+)

       printenv [name] (+)
               Prints the names and  values  of  all  environment
               variables or, with name, the value of the environ-
               ment variable name.

       pushd [-p] [-l] [-n|-v] [name|+n]
               Without arguments, exchanges the top two  elements
               of  the  directory  stack.  If pushdtohome is set,
               pushd without arguments does `pushd ~',  like  cd.
               (+)  With  name, pushes the current working direc-
               tory onto the directory stack and changes to name.
               If  name  is `-' it is interpreted as the previous
               working directory (see Filename substitution). (+)
               If  dunique is set, pushd removes any instances of
               name from the stack before  pushing  it  onto  the
               stack.  (+)  With  a  number `+n', rotates the nth
               element of the directory stack around  to  be  the
               top  element  and  changes  to it.  If dextract is
               set, however, `pushd +n' extracts the  nth  direc-
               tory,  pushes  it  onto  the  top of the stack and
               changes to it. (+)

               Finally, all forms of pushd print the final direc-
               tory  stack, just like dirs. The pushdsilent shell
               variable can be set to prevent  this  and  the  -p
               flag  can  be  given to override pushdsilent.  The
               -l, -n and -v flags have the same effect on  pushd
               as on dirs. (+)

       rehash  Causes  the internal hash table of the contents of
               the directories in the path variable to be  recom-
               puted.   This  is needed if new commands are added
               to directories in path while you  are  logged  in.
               This  should only be necessary if you add commands
               to one of your own directories, or  if  a  systems
               programmer changes the contents of one of the sys-
               tem directories. Also flushes the  cache  of  home
               directories built by tilde expansion.

       repeat count command
               The  specified  command,  which  is subject to the
               same restrictions as the command in the  one  line
               if  statement above, is executed count times.  I/O
               redirections occur exactly once, even if count  is
               0.

       rootnode //nodename (+)
               Changes  the  rootnode  to //nodename, so that `/'
               will be interpreted  as  `//nodename'.  (Domain/OS
               only)

       sched (+)
       sched [+]hh:mm command (+)
       sched -n (+)
               The  first  form  prints the scheduled-event list.
               The sched shell variable may be set to define  the
               format   in  which  the  scheduled-event  list  is
               printed.  The second  form  adds  command  to  the
               scheduled-event list.  For example,

                   > sched 11:00 echo It\'s eleven o\'clock.

               causes the shell to echo `It's eleven o'clock.' at
               11 AM.  The time may be in 12-hour AM/PM format

                   > sched 5pm set prompt='[%h] It\'s after 5; go
                   home: >'

               or may be relative to the current time:

                   > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

               A relative time specification may  not  use  AM/PM
               format.   The  third  form removes item n from the
               event list:

                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico
                   -r1 -sother
                        2  Wed Apr  4 17:00  set prompt=[%h] It's
                   after 5; go home: >
                   > sched -2
                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico
                   -r1 -sother

               A  command in the scheduled-event list is executed
               just before the first prompt is printed after  the
               time  when the command is scheduled.  It is possi-
               ble to miss the exact time when the command is  to
               be run, but an overdue command will execute at the
               next prompt.  A command which comes due while  the
               shell  is waiting for user input is executed imme-
               diately.  However, normal operation of an already-
               running  command will not be interrupted so that a
               scheduled-event list element may be run.

               This mechanism is similar to, but not the same as,
               the at(1) command on some Unix systems.  Its major
               disadvantage is that it may not run a  command  at
               exactly  the  specified time.  Its major advantage
               is that  because  sched  runs  directly  from  the
               shell,  it has access to shell variables and other
               structures.  This provides a mechanism for  chang-
               ing one's working environment based on the time of
               day.

       set
       set name ...
       set name=word ...
       set [-r] [-f|-l] name=(wordlist) ... (+)
       set name[index]=word ...
       set -r (+)
       set -r name ... (+)
       set -r name=word ... (+)
               The first form of the command prints the value  of
               all shell variables.  Variables which contain more
               than a single word print as a  parenthesized  word
               list.   The  second  form  sets  name  to the null
               string.  The third form sets name  to  the  single
               word.   The  fourth  form sets name to the list of
               words in wordlist. In all cases the value is  com-
               mand  and  filename expanded.  If -r is specified,
               the value is set read-only. If -f or -l are speci-
               fied,  set  only unique words keeping their order.
               -f prefers the first occurrence of a word, and  -l
               the  last.   first occurance of the word The fifth
               form sets the index'th component of name to  word;
               this component must already exist.  The sixth form
               lists the names  (only)  of  all  shell  variables
               which  are read-only.  The seventh form makes name
               read-only, whether or not it  has  a  value.   The
               second  form  sets  name  to the null string.  The
               eighth form is the same as  the  third  form,  but
               make name read-only at the same time.

               These arguments can be repeated to set and/or make
               read-only multiple variables in a single set  com-
               mand.  Note, however, that variable expansion hap-
               pens for all arguments before any setting  occurs.
               Note  also  that  `=' can be adjacent to both name
               and word or separated from both by whitespace, but
               cannot  be adjacent to only one or the other.  See
               also the unset builtin command.

       setenv [name [value]]
               Without arguments, prints the names and values  of
               all  environment  variables.  Given name, sets the
               environment variable name  to  value  or,  without
               value, to the null string.

       setpath path (+)
               Equivalent to setpath(1). (Mach only)

       setspath LOCAL|site|cpu ... (+)
               Sets the system execution path. (TCF only)

       settc cap value (+)
               Tells the shell to believe that the terminal capa-
               bility cap (as  defined  in  termcap(5))  has  the
               value value.  No sanity checking is done.  Concept
               terminal users may have to `settc xn  no'  to  get
               proper wrapping at the rightmost column.

       setty [-d|-q|-x] [-a] [[+|-]mode] (+)
               Controls which tty modes (see Terminal management)
               the shell does not allow to change.  -d, -q or  -x
               tells setty to act on the `edit', `quote' or `exe-
               cute' set of tty modes respectively;  without  -d,
               -q or -x, `execute' is used.

               Without  other arguments, setty lists the modes in
               the chosen set which are fixed on (`+mode') or off
               (`-mode').  The available modes, and thus the dis-
               play, vary from system to system.  With -a,  lists
               all  tty  modes  in  the chosen set whether or not
               they are fixed.  With +mode, -mode or mode,  fixes
               mode on or off or removes control from mode in the
               chosen set.  For  example,  `setty  +echok  echoe'
               fixes  `echok' mode on and allows commands to turn
               `echoe' mode on or off, both  when  the  shell  is
               executing commands.

       setxvers [string] (+)
               Set  the experimental version prefix to string, or
               removes it if string is omitted. (TCF only)

       shift [variable]
               Without arguments, discards argv[1] and shifts the
               members  of  argv  to the left. It is an error for
               argv not to be set or to have less than  one  word
               as  value.  With variable, performs the same func-
               tion on variable.

       source [-h] name [args ...]
               The shell reads and executes commands  from  name.
               The  commands  are not placed on the history list.
               If any args are given, they are  placed  in  argv.
               (+)  source  commands  may  be nested; if they are
               nested too deeply the shell may run  out  of  file
               descriptors.   An  error  in a source at any level
               terminates all nested source commands.   With  -h,
               commands are placed on the history list instead of
               being executed, much like `history -L'.

       stop %job|pid ...
               Stops the specified jobs or  processes  which  are
               executing in the background.  job may be a number,
               a string, `', `%', `+' or `-' as  described  under
               Jobs.  There is no default job; saying just `stop'
               does not stop the current job.

       suspend Causes the shell to stop in its tracks, much as if
               it  had  been  sent a stop signal with ^Z. This is
               most often used to stop shells started by su(1).

       switch (string)
       case str1:
           ...
           breaksw
       ...
       default:
           ...
           breaksw
       endsw   Each case label is successively  matched,  against
               the  specified  string  which is first command and
               filename expanded.  The file  metacharacters  `*',
               `?'  and  `[...]'  may be used in the case labels,
               which are  variable  expanded.   If  none  of  the
               labels  match  before  a `default' label is found,
               then the execution begins after the default label.
               Each  case label and the default label must appear
               at the beginning of a line.  The  command  breaksw
               causes execution to continue after the endsw. Oth-
               erwise control may fall through  case  labels  and
               default  labels  as in C.  If no label matches and
               there is no default, execution continues after the
               endsw.

       telltc (+)
               Lists the values of all terminal capabilities (see
               termcap(5)).

       time [command]
               Executes command (which must be a simple  command,
               not  an  alias,  a  pipeline,  a command list or a
               parenthesized command list) and prints a time sum-
               mary  as  described  under  the time variable.  If
               necessary, an extra shell is created to print  the
               time  statistic when the command completes.  With-
               out command, prints a time summary for the current
               shell and its children.

       umask [value]
               Sets  the  file  creation  mask to value, which is
               given in octal.  Common values for  the  mask  are
               002,  giving  all access to the group and read and
               execute access to others, and 022, giving read and
               execute  access  to the group and others.  Without
               value, prints the current file creation mask.

       unalias pattern
               Removes all aliases  whose  names  match  pattern.
               `unalias  *'  thus removes all aliases.  It is not
               an error for nothing to be unaliased.

       uncomplete pattern (+)
               Removes all completions whose names match pattern.
               `uncomplete  *'  thus removes all completions.  It
               is not an error for nothing to be uncompleted.

       unhash  Disables use of the internal hash table  to  speed
               location of executed programs.

       universe universe (+)
               Sets the universe to universe. (Masscomp/RTU only)

       unlimit [-h] [resource]
               Removes the  limitation  on  resource  or,  if  no
               resource  is  specified, all resource limitations.
               With  -h,  the  corresponding  hard   limits   are
               removed.  Only the super-user may do this.

       unset pattern
               Removes  all  variables whose names match pattern,
               unless they are read-only.  `unset *' thus removes
               all variables unless they are read-only; this is a
               bad idea.  It is not an error for  nothing  to  be
               unset.

       unsetenv pattern
               Removes  all  environment  variables  whose  names
               match pattern.   `unsetenv  *'  thus  removes  all
               environment  variables; this is a bad idea.  It is
               not an error for nothing to be unsetenved.

       ver [systype [command]] (+)
               Without arguments, prints SYSTYPE.  With  systype,
               sets SYSTYPE to systype. With systype and command,
               executes command under  systype.  systype  may  be
               `bsd4.3' or `sys5.3'.  (Domain/OS only)

       wait    The  shell  waits for all background jobs.  If the
               shell is interactive, an  interrupt  will  disrupt
               the  wait  and  cause the shell to print the names
               and job numbers of all outstanding jobs.

       warp universe (+)
               Sets the universe to universe. (Convex/OS only)

       watchlog (+)
               An alternate name  for  the  log  builtin  command
               (q.v.).   Available  only if the shell was so com-
               piled; see the version shell variable.

       where command (+)
               Reports all known instances of command,  including
               aliases, builtins and executables in path.

       which command (+)
               Displays  the command that will be executed by the
               shell after substitutions,  path  searching,  etc.
               The  builtin command is just like which(1), but it
               correctly reports tcsh aliases and builtins and is
               10  to  100 times faster.  See also the which-com-
               mand editor command.

       while (expr)
       ...
       end     Executes the commands between the  while  and  the
               matching   end   while  expr  (an  expression,  as
               described under Expressions)  evaluates  non-zero.
               while  and  end  must  appear alone on their input
               lines.  break and continue may be used  to  termi-
               nate  or  continue  the  loop prematurely.  If the
               input is a terminal,  the  user  is  prompted  the
               first time through the loop as with foreach.

   Special aliases (+)
       If  set,  each  of these aliases executes automatically at
       the indicated time.  They are all initially undefined.

       beepcmd Runs when the shell wants  to  ring  the  terminal
               bell.

       cwdcmd  Runs  after every change of working directory. For
               example, if the user is working  on  an  X  window
               system  using  xterm(1)  and a re-parenting window
               manager that supports title bars  such  as  twm(1)
               and does

                   >  alias  cwdcmd   'echo -n "^[]2;${HOST}:$cwd
                   ^G"'

               then the shell will change the title of  the  run-
               ning xterm(1) to be the name of the host, a colon,
               and the full current working directory.  A fancier
               way to do that is

                   >       alias       cwdcmd       'echo      -n
                   "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'

               This will put the hostname and  working  directory
               on the title bar but only the hostname in the icon
               manager menu.

               Note that putting a cd, pushd or  popd  in  cwdcmd
               may  cause  an  infinite  loop. It is the author's
               opinion that anyone doing so will  get  what  they
               deserve.

       periodic
               Runs every tperiod minutes. This provides a conve-
               nient means for checking on common but  infrequent
               changes such as new mail. For example, if one does

                   > set tperiod = 30
                   > alias periodic checknews

               then the checknews(1) program runs every  30  min-
               utes.   If periodic is set but tperiod is unset or
               set to 0, periodic behaves like precmd.

       precmd  Runs just before each prompt is printed. For exam-
               ple, if one does

                   > alias precmd date

               then  date(1)  runs  just before the shell prompts
               for each command.  There are  no  limits  on  what
               precmd  can be set to do, but discretion should be
               used.

       shell   Specifies the interpreter for  executable  scripts
               which  do  not  themselves specify an interpreter.
               The first word should be a full path name  to  the
               desired    interpreter    (e.g.    `/bin/csh'   or
               `/usr/local/bin/tcsh').

   Special shell variables
       The variables described in this section have special mean-
       ing to the shell.

       The  shell  sets  addsuffix,  argv,  autologout,  command,
       echo_style, edit, gid, group, home,  loginsh,  oid,  path,
       prompt,  prompt2,  prompt3, shell, shlvl, tcsh, term, tty,
       uid, user and version  at  startup;  they  do  not  change
       thereafter  unless  changed by the user. The shell updates
       cwd, dirstack, owd and status  when  necessary,  and  sets
       logout on logout.

       The  shell synchronizes afsuser, group, home, path, shlvl,
       term and user with the environment variables of  the  same
       names: whenever the environment variable changes the shell
       changes the corresponding shell variable to match  (unless
       the shell variable is read-only) and vice versa. Note that
       although cwd and PWD have identical meanings, they are not
       synchronized  in this manner, and that the shell automati-
       cally interconverts the  different  formats  of  path  and
       PATH.

       addsuffix (+)
               If set, filename completion adds `/' to the end of
               directories and a space to the end of normal files
               when they are matched exactly.  Set by default.

       afsuser (+)
               If  set,  autologout's  autolock  feature uses its
               value instead of the local username  for  kerberos
               authentication.

       ampm (+)
               If  set, all times are shown in 12-hour AM/PM for-
               mat.

       argv    The arguments to the shell. Positional  parameters
               are  taken  from  argv,  i.e.  `$1' is replaced by
               `$argv[1]', etc.   Set  by  default,  but  usually
               empty in interactive shells.

       autocorrect (+)
               If  set,  the spell-word editor command is invoked
               automatically before each completion attempt.

       autoexpand (+)
               If  set,  the  expand-history  editor  command  is
               invoked   automatically   before  each  completion
               attempt.

       autolist (+)
               If set, possibilities are listed after an  ambigu-
               ous completion.  If set to `ambiguous', possibili-
               ties are listed only when no  new  characters  are
               added by completion.

       autologout (+)
               The  first  word is the number of minutes of inac-
               tivity before automatic logout. The optional  sec-
               ond  word  is  the number of minutes of inactivity
               before automatic locking.  When the shell automat-
               ically logs out, it prints `auto-logout', sets the
               variable logout to `automatic'  and  exits.   When
               the   shell   automatically  locks,  the  user  is
               required to enter his password to  continue  work-
               ing.  Five  incorrect attempts result in automatic
               logout.  Set to `60' (automatic  logout  after  60
               minutes,  and  no locking) by default in login and
               superuser shells, but not if the shell  thinks  it
               is running under a window system (i.e. the DISPLAY
               environment variable is set), the tty is a pseudo-
               tty  (pty)  or  the shell was not so compiled (see
               the version shell variable).  See also the afsuser
               and logout shell variables.

       backslash_quote (+)
               If  set,  backslashes (`\') always quote `\', `'',
               and `"'. This may make complex quoting tasks  eas-
               ier,  but  it  can  cause  syntax errors in csh(1)
               scripts.

       cdpath  A list of directories in which  cd  should  search
               for  subdirectories  if  they  aren't found in the
               current directory.

       color   If set, it enables color display for  the  builtin
               ls-F  and  it  passes --color=auto to ls. Alterna-
               tively, it can be set to only ls-F or only  ls  to
               enable  color  only  to one command. Setting it to
               nothing is equivalent to setting it to (ls-F  ls).

       command (+)
               If  set, the command which was passed to the shell
               with the -c flag (q.v.).

       complete (+)
               If set to `enhance', completion  1)  ignores  case
               and  2) considers periods, hyphens and underscores
               (`.', `-' and  `_')  to  be  word  separators  and
               hyphens and underscores to be equivalent.

       correct (+)
               If   set  to  `cmd',  commands  are  automatically
               spelling-corrected.  If set  to  `complete',  com-
               mands  are  automatically  completed.   If  set to
               `all', the entire command line is corrected.

       cwd     The full pathname of the current  directory.   See
               also the dirstack and owd shell variables.

       dextract (+)
               If set, `pushd +n' extracts the nth directory from
               the directory stack rather than rotating it to the
               top.

       dirsfile (+)
               The  default location in which `dirs -S' and `dirs
               -L' look for a history file. If unset,  ~/.cshdirs
               is  used.   Because  only  ~/.tcshrc  is  normally
               sourced before ~/.cshdirs, dirsfile should be  set
               in ~/.tcshrc rather than ~/.login.

       dirstack (+)
               An  array  of all the directories on the directory
               stack.   `$dirstack[1]'  is  the  current  working
               directory,  `$dirstack[2]'  the first directory on
               the stack, etc.  Note  that  the  current  working
               directory  is `$dirstack[1]' but `=0' in directory
               stack substitutions,  etc.   One  can  change  the
               stack  arbitrarily  by  setting  dirstack, but the
               first element (the current working  directory)  is
               always  correct.   See  also the cwd and owd shell
               variables.

       dspmbyte (+)
               If set to `euc', it enables  display  and  editing
               EUC-kanji(japanese)  code.   If  set to `sjis', it
               enables display  and  editing  Shift-JIS(japanese)
               code.  If set to following format, it enables dis-
               play and editing original multi-byte code format:

                   > set dspkanji = 0000....(256 bytes)....0000

               table length require just 256 byte. Each character
               of  256  characters corresponds from the left from
               0x01,0x02... to 0xff of ASCII code. Each character
               is  set to number 0,1,2 and 3. Each number has the
               following meanings:
                 0 ... not use for multi-byte character.
                 1 ... use for first byte of multi-byte charcter.
                 2  ... use for second byte of multi-byte charac-
               ter.
                 3 ... use for both of first byte and second byte
               of multi-byte character.
                 Exapmle:
                   if set `001322', first character(means 0x00 of
               ASCII code) and  second  character(means  0x01  of
               ASCII code) is set to `0'. then, it is not use for
               multi-byte character.3rd  character(0x02)  is  set
               '2'. it is use for first byte of multi-byte charc-
               ter. 4th character(0x03) is set '3'. it is use for
               both  of  first byte and second byte of multi-byte
               character. 5th and 6th character(0x04,0x05) is set
               '2'.  it  is  use  for  second  byte of multi-byte
               charcter.

       dunique (+)
               If set, pushd removes any instances of  name  from
               the stack before pushing it onto the stack.

       echo    If  set, each command with its arguments is echoed
               just before it is executed.  For non-builtin  com-
               mands   all   expansions   occur  before  echoing.
               Builtin commands are  echoed  before  command  and
               filename  substitution,  since these substitutions
               are then done selectively.  Set by the -x  command
               line option.

       echo_style (+)
               The style of the echo builtin. May be set to

               bsd     Don't echo a newline if the first argument
                       is `-n'.
               sysv    Recognize backslashed escape sequences  in
                       echo strings.
               both    Recognize  both  the  `-n'  flag and back-
                       slashed escape sequences; the default.
               none    Recognize neither.

               Set by default to the local  system  default.  The
               BSD  and  System  V  options  are described in the
               echo(1) manpages on the appropriate systems.

       edit (+)
               If set, the command-line editor is used.   Set  by
               default in interactive shells.

       ellipsis (+)
               If  set,  the  `%c'/`%.' and `%C' prompt sequences
               (see the prompt shell variable)  indicate  skipped
               directories  with  an ellipsis (`...')  instead of
               `/<skipped>'.

       fignore (+)
               Lists file name suffixes to be ignored by  comple-
               tion.

       filec   In  tcsh, completion is always used and this vari-
               able is ignored.  If set in csh, filename  comple-
               tion is used.

       gid (+) The user's real group ID.

       group (+)
               The user's group name.

       histchars
               A  string value determining the characters used in
               History substitution (q.v.).  The first  character
               of  its  value is used as the history substitution
               character, replacing the  default  character  `!'.
               The  second  character  of  its value replaces the
               character `^' in quick substitutions.

       histdup (+)
               Controls handling of duplicate entries in the his-
               tory  list.   If  set to `all' only unique history
               events are entered in the history list. If set  to
               `prev'  and  the last history event is the same as
               the current command, then the current  command  is
               not entered in the history.  If set to `erase' and
               the same event is found in the history list,  that
               old  event  gets  erased  and the current one gets
               inserted. Note that the `prev' and  `all'  options
               renumber history events so there are no gaps.

       histfile (+)
               The  default  location  in  which `history -S' and
               `history -L' look for a history  file.  If  unset,
               ~/.history is used.  histfile is useful when shar-
               ing the  same  home  directory  between  different
               machines,  or  when  saving  separate histories on
               different terminals.  Because  only  ~/.tcshrc  is
               normally   sourced   before  ~/.history,  histfile
               should be set in ~/.tcshrc rather than ~/.login.

       histlit (+)
               If set, builtin and editor commands and the  save-
               hist  mechanism  use the literal (unexpanded) form
               of lines in the history list.  See also  the  tog-
               gle-literal-history editor command.

       history The  first  word  indicates  the number of history
               events to save.   The  optional  second  word  (+)
               indicates  the format in which history is printed;
               if not given, `%h\t%T\t%R\n' is used.  The  format
               sequences  are  described below under prompt; note
               the variable meaning of `%R'.   Set  to  `100'  by
               default.

       home    Initialized  to the home directory of the invoker.
               The filename expansion of `~' refers to this vari-
               able.

       ignoreeof
               If  set  to  the empty string or `0' and the input
               device is  a  terminal,  the  end-of-file  command
               (usually  generated  by the user by typing `^D' on
               an empty line) causes  the  shell  to  print  `Use
               "exit"  to  leave tcsh.' instead of exiting.  This
               prevents the shell from accidentally being killed.
               If set to a number n, the shell ignores n - 1 con-
               secutive end-of-files and exits on the nth. (+) If
               unset, `1' is used, i.e. the shell exits on a sin-
               gle `^D'.

       implicitcd (+)
               If set, the shell treats a directory name typed as
               a command as though it were a request to change to
               that directory. If set to verbose, the  change  of
               directory  is  echoed to the standard output. This
               behavior is  inhibited  in  non-interactive  shell
               scripts, or for command strings with more than one
               word. Changing  directory  takes  precedence  over
               executing  a  like-named  command,  but it is done
               after  alias  substitutions.  Tilde  and  variable
               expansions work as expected.

       inputmode (+)
               If set to `insert' or `overwrite', puts the editor
               into that input mode  at  the  beginning  of  each
               line.

       listflags (+)
               If  set  to  `x',  `a'  or `A', or any combination
               thereof (e.g. `xA'), they are  used  as  flags  to
               ls-F,  making  it act like `ls -xF', `ls -Fa', `ls
               -FA' or a combination (e.g. `ls -FxA'): `a'  shows
               all  files  (even  if  they start with a `.'), `A'
               shows all files but `.' and `..',  and  `x'  sorts
               across  instead  of  down.   If the second word of
               listflags is set,  it  is  used  as  the  path  to
               `ls(1)'.

       listjobs (+)
               If  set,  all  jobs  are listed when a job is sus-
               pended. If set to `long', the listing is  in  long
               format.

       listlinks (+)
               If set, the ls-F builtin command shows the type of
               file to which each symbolic link points.

       listmax (+)
               The maximum number of items which the list-choices
               editor command will list without asking first.

       listmaxrows (+)
               The  maximum  number  of  rows  of items which the
               list-choices editor command will list without ask-
               ing first.

       loginsh (+)
               Set  by the shell if it is a login shell.  Setting
               or unsetting it within a shell has no effect.  See
               also shlvl.

       logout (+)
               Set  by  the  shell  to  `normal'  before a normal
               logout, `automatic' before  an  automatic  logout,
               and  `hangup'  if the shell was killed by a hangup
               signal (see Signal handling).  See also the autol-
               ogout shell variable.

       mail    The names of the files or directories to check for
               incoming  mail,  separated  by   whitespace,   and
               optionally  preceeded  by  a numeric word.  Before
               each prompt, if 10 minutes have passed  since  the
               last  check,  the  shell checks each file and says
               `You have new mail.' (or, if mail contains  multi-
               ple  files,  `You  have new mail in name.') if the
               filesize is greater than zero in size  and  has  a
               modification time greater than its access time.

               If  you are in a login shell, then no mail file is
               reported unless it has  been  modified  after  the
               time the shell has started up, in order to prevent
               redundant notifications.  Most login programs will
               tell you whether or not you have mail when you log
               in.

               If a file specified in mail is  a  directory,  the
               shell  will  count each file within that directory
               as a separate message, and will report `You have n
               mails.'  or  `You have n mails in name.' as appro-
               priate.  This functionality is provided  primarily
               for those systems which store mail in this manner,
               such as the Andrew Mail System.

               If the first word of mail is numeric it  is  taken
               as a different mail checking interval, in seconds.

               Under  very  rare  circumstances,  the  shell  may
               report  `You  have mail.' instead of `You have new
               mail.'

       matchbeep (+)
               If set to `never', completion never beeps.  If set
               to  `nomatch',  it  beeps  only  when  there is no
               match.  If set to `ambiguous, it beeps when  there
               are  multiple  matches.  If set to `notunique', it
               beeps when there is one  exact  and  other  longer
               matches.  If unset, `ambiguous' is used.

       nobeep (+)
               If  set, beeping is completely disabled.  See also
               visiblebell.

       noclobber
               If set, restrictions are placed on output redirec-
               tion  to  insure  that  files are not accidentally
               destroyed and  that  `>>'  redirections  refer  to
               existing  files,  as described in the Input/output
               section.

       noglob  If set, Filename substitution and Directory  stack
               substitution  (q.v.)  are inhibited.  This is most
               useful in shell scripts which  do  not  deal  with
               filenames,  or  after a list of filenames has been
               obtained and further expansions are not desirable.

       nokanji (+)
               If  set and the shell supports Kanji (see the ver-
               sion shell variable), it is disabled so  that  the
               meta key can be used.

       nonomatch
               If set, a Filename substitution or Directory stack
               substitution  (q.v.)  which  does  not  match  any
               existing files is left untouched rather than caus-
               ing an error.  It is still an error for  the  sub-
               stitution  to  be  malformed,  e.g. `echo [' still
               gives an error.

       nostat (+)
               A list  of  directories  (or  glob-patterns  which
               match directories; see Filename substitution) that
               should not be stat(2)ed during a completion opera-
               tion.  This is usually used to exclude directories
               which take too much time to stat(2),  for  example
               /afs.

       notify  If  set, the shell announces job completions asyn-
               chronously.  The default is to present job comple-
               tions just before printing a prompt.

       oid (+) The user's real organization ID. (Domain/OS only)

       owd (+) The  old  working directory, equivalent to the `-'
               used by cd  and  pushd.   See  also  the  cwd  and
               dirstack shell variables.

       path    A  list  of  directories in which to look for exe-
               cutable commands.  A null word specifies the  cur-
               rent directory.  If there is no path variable then
               only full path names will execute.  path is set by
               the  shell  at  startup  from the PATH environment
               variable or, if PATH does not exist, to a  system-
               dependent  default something like `(/usr/local/bin
               /usr/bsd /bin /usr/bin .)'.  The shell may put `.'
               first  or last in path or omit it entirely depend-
               ing on how it was compiled; see the version  shell
               variable.   A  shell which is given neither the -c
               nor the -t  option  hashes  the  contents  of  the
               directories  in  path  after reading ~/.tcshrc and
               each time path is reset.  If one adds a  new  com-
               mand  to  a  directory  in path while the shell is
               active, one may need to do a rehash for the  shell
               to find it.

       printexitvalue (+)
               If  set  and  an  interactive program exits with a
               non-zero status, the shell prints `Exit status'.

       prompt  The string which is printed  before  reading  each
               command from the terminal.  prompt may include any
               of the following formatting sequences  (+),  which
               are replaced by the given information:

               %/  The current working directory.
               %~  The  current working directory, but with one's
                   home directory represented by  `~'  and  other
                   users' home directories represented by `~user'
                   as per Filename substitution. `~user'  substi-
                   tution  happens  only if the shell has already
                   used `~user' in a pathname in the current ses-
                   sion.
               %c[[0]n], %.[[0]n]
                   The  trailing component of the current working
                   directory, or n trailing components if a digit
                   n  is given.  If n begins with `0', the number
                   of skipped  components  precede  the  trailing
                   component(s)  in  the format `/<skipped>trail-
                   ing'.  If the ellipsis shell variable is  set,
                   skipped   components  are  represented  by  an
                   ellipsis so the whole  becomes  `...trailing'.
                   `~' substitution is done as in `%~' above, but
                   the `~' component  is  ignored  when  counting
                   trailing components.
               %C  Like %c, but without `~' substitution.
               %h, %!, !
                   The current history event number.
               %M  The full hostname.
               %m  The hostname up to the first `.'.
               %S (%s)
                   Start (stop) standout mode.
               %B (%b)
                   Start (stop) boldfacing mode.
               %U (%u)
                   Start (stop) underline mode.
               %t, %@
                   The time of day in 12-hour AM/PM format.
               %T  Like  `%t', but in 24-hour format (but see the
                   ampm shell variable).
               %p  The `precise' time of  day  in  12-hour  AM/PM
                   format, with seconds.
               %P  Like  `%p', but in 24-hour format (but see the
                   ampm shell variable).
               \c  c is parsed as in bindkey.
               ^c  c is parsed as in bindkey.
               %%  A single `%'.
               %n  The user name.
               %d  The weekday in `Day' format.
               %D  The day in `dd' format.
               %w  The month in `Mon' format.
               %W  The month in `mm' format.
               %y  The year in `yy' format.
               %Y  The year in `yyyy' format.
               %l  The shell's tty.
               %L  Clears from the end of the prompt  to  end  of
                   the display or the end of the line.
               %$  Expands the shell or environment variable name
                   immediately after the `$'.
               %#  `>' (or the first character of the promptchars
                   shell  variable) for normal users, `#' (or the
                   second character of promptchars) for the supe-
                   ruser.
               %{string%}
                   Includes  string as a literal escape sequence.
                   It should be  used  only  to  change  terminal
                   attributes  and  should  not  move  the cursor
                   location. This cannot be the last sequence  in
                   prompt.
               %?  The  return  code of the command executed just
                   before the prompt.
               %R  In prompt2, the  status  of  the  parser.   In
                   prompt3,  the  corrected  string.  In history,
                   the history string.

               `%B', `%S', `%U' and  `%{string%}'  are  available
               only  in  eight-bit-clean  shells; see the version
               shell variable.

               The bold, standout  and  underline  sequences  are
               often  used  to distinguish a superuser shell. For
               example,

                   > set prompt =  "%m  [%h]  %B[%@]%b  [%/]  you
                   rang? "
                   tut [37] [2:54pm] [/usr/accts/sys] you rang? _

               Set by default to `%# ' in interactive shells.

       prompt2 (+)
               The string with which to prompt in while and fore-
               ach loops and after lines ending in `\'.  The same
               format sequences may be used as in prompt  (q.v.);
               note the variable meaning of `%R'.  Set by default
               to `%R? ' in interactive shells.

       prompt3 (+)
               The string with which to  prompt  when  confirming
               automatic  spelling  correction.   The same format
               sequences may be used as in  prompt  (q.v.);  note
               the  variable  meaning of `%R'.  Set by default to
               `CORRECT>%R (y|n|e|a)? ' in interactive shells.

       promptchars (+)
               If set (to a two-character string), the `%#'  for-
               matting  sequence  in the prompt shell variable is
               replaced with the first character for normal users
               and the second character for the superuser.

       pushdtohome (+)
               If  set,  pushd  without arguments does `pushd ~',
               like cd.

       pushdsilent (+)
               If set, pushd and popd do not print the  directory
               stack.

       recexact (+)
               If  set,  completion  completes  on an exact match
               even if a longer match is possible.

       recognize_only_executables (+)
               If set, command listing displays only files in the
               path that are executable. Slow.

       rmstar (+)
               If set, the user is prompted before `rm *' is exe-
               cuted.

       rprompt (+)
               The string to print on the right-hand side of  the
               screen  (after  the command input) when the prompt
               is being displayed on the left.  It recognises the
               same  formatting  characters  as  prompt.  It will
               automatically disappear and reappear as necessary,
               to  ensure  that command input isn't obscured, and
               will only appear if the prompt, command input, and
               itself  will  fit  together on the first line.  If
               edit isn't set, then rprompt will be printed after
               the prompt and before the command input.

       savedirs (+)
               If set, the shell does `dirs -S' before exiting.

       savehist
               If  set,  the shell does `history -S' before exit-
               ing.  If the first word is set  to  a  number,  at
               most  that many lines are saved.  (The number must
               be less than or equal to history.)  If the  second
               word is set to `merge', the history list is merged
               with the existing history file instead of  replac-
               ing  it (if there is one) and sorted by time stamp
               and the most recent events are retained. (+)

       sched (+)
               The format in  which  the  sched  builtin  command
               prints    scheduled    events;   if   not   given,
               `%h\t%T\t%R\n' is used.  The format sequences  are
               described  above  under  prompt; note the variable
               meaning of `%R'.

       shell   The file in which the shell resides.  This is used
               in  forking  shells  to interpret files which have
               execute bits set, but which are not executable  by
               the  system.   (See the description of Builtin and
               non-builtin command  execution.)   Initialized  to
               the (system-dependent) home of the shell.

       shlvl (+)
               The  number of nested shells.  Reset to 1 in login
               shells.  See also loginsh.

       status  The status returned by the last  command.   If  it
               terminated  abnormally,  then 0200 is added to the
               status.  Builtin commands which fail  return  exit
               status `1', all other builtin commands return sta-
               tus `0'.

       symlinks (+)
               Can be set to several different values to  control
               symbolic link (`symlink') resolution:

               If  set to `chase', whenever the current directory
               changes to a directory containing a symbolic link,
               it  is  expanded to the real name of the directory
               to which the link points. This does not  work  for
               the user's home directory; this is a bug.

               If set to `ignore', the shell tries to construct a
               current directory relative to the  current  direc-
               tory before the link was crossed.  This means that
               cding through a symbolic link and then `cd  ..'ing
               returns  one  to the original directory. This only
               affects builtin commands and filename  completion.

               If  set  to  `expand', the shell tries to fix sym-
               bolic links by actually expanding arguments  which
               look  like  path  names. This affects any command,
               not just builtins. Unfortunately,  this  does  not
               work  for  hard-to-recognize  filenames,  such  as
               those embedded in command options.  Expansion  may
               be  prevented  by  quoting.  While this setting is
               usually the most convenient, it is sometimes  mis-
               leading  and  sometimes confusing when it fails to
               recognize an argument which should be expanded.  A
               compromise  is  to use `ignore' and use the editor
               command normalize-path (bound by default to  ^X-n)
               when necessary.

               Some  examples  are  in order. First, let's set up
               some play directories:

                   > cd /tmp
                   > mkdir from from/src to
                   > ln -s from/src to/dist

               Here's the behavior with symlinks unset,

                   > cd /tmp/to/dist; echo $cwd
                   /tmp/to/dist
                   > cd ..; echo $cwd
                   /tmp/from

               here's the behavior with symlinks set to `chase',

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/from/src
                   > cd ..; echo $cwd
                   /tmp/from

               here's the behavior with symlinks set to `ignore',

                   > cd /tmp/to/dist; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/to

               and  here's  the  behavior  with  symlinks  set to
               `expand'.

                   > cd /tmp/to/dist; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/to
                   > cd /tmp/to/dist; echo $cwd
                   /tmp/to/dst
                   > cd ".."; echo $cwd
                   /tmp/from
                   > /bin/echo ..
                   /tmp/to
                   > /bin/echo ".."
                   ..

               Note that `expand' expansion 1)  works  just  like
               `ignore'  for builtins like cd, 2) is prevented by
               quoting,  and  3)  happens  before  filenames  are
               passed to non-builtin commands.

       tcsh (+)
               The  version  number  of  the  shell in the format
               `R.VV.PP', where `R' is the major release  number,
               `VV'  the current version and `PP' the patchlevel.

       term    The terminal type.  Usually  set  in  ~/.login  as
               described under Startup and shutdown.

       time    If  set  to a number, then the time builtin (q.v.)
               executes automatically after  each  command  which
               takes  more  than that many CPU seconds.  If there
               is a second word, it is used as  a  format  string
               for  the  output of the time builtin. (u) The fol-
               lowing sequences may be used in the format string:

               %U  The time the process spent in user mode in cpu
                   seconds.
               %S  The time the process spent in kernel  mode  in
                   cpu seconds.
               %E  The elapsed (wall clock) time in seconds.
               %P  The CPU percentage computed as (%U + %S) / %E.
               %W  Number of times the process was swapped.
               %X  The average amount in (shared) text space used
                   in Kbytes.
               %D  The  average  amount  in (unshared) data/stack
                   space used in Kbytes.
               %K  The total space used (%X + %D) in Kbytes.
               %M  The maximum memory the process had in  use  at
                   any time in Kbytes.
               %F  The  number  of major page faults (page needed
                   to be brought from disk).
               %R  The number of minor page faults.
               %I  The number of input operations.
               %O  The number of output operations.
               %r  The number of socket messages received.
               %s  The number of socket messages sent.
               %k  The number of signals received.
               %w  The  number  of  voluntary  context   switches
                   (waits).
               %c  The number of involuntary context switches.

               Only  the  first  four  sequences are supported on
               systems without BSD resource limit functions.  The
               default  time  format  is  `%Uu  %Ss  %E %P %X+%Dk
               %I+%Oio  %Fpf+%Ww'  for   systems   that   support
               resource  usage  reporting and `%Uu %Ss %E %P' for
               systems that do not.

               Under Sequent's DYNIX/ptx, %X, %D, %K, %r  and  %s
               are  not  available,  but the following additional
               sequences are:

               %Y  The number of system calls performed.
               %Z  The number of pages which are  zero-filled  on
                   demand.
               %i  The  number  of times a process's resident set
                   size was increased by the kernel.
               %d  The number of times a process's  resident  set
                   size was decreased by the kernel.
               %l  The number of read system calls performed.
               %m  The number of write system calls performed.
               %p  The number of reads from raw disk devices.
               %q  The number of writes to raw disk devices.

               and  the  default  time  format  is `%Uu %Ss $E %P
               %I+%Oio %Fpf+%Ww'.  Note that the  CPU  percentage
               can be higher than 100% on multi-processors.

       tperiod (+)
               The  period, in minutes, between executions of the
               periodic special alias.

       tty (+) The name of the tty, or empty if not  attached  to
               one.

       uid (+) The user's real user ID.

       user    The user's login name.

       verbose If  set,  causes  the  words of each command to be
               printed, after history substitution (if any).  Set
               by the -v command line option.

       version (+)
               The version ID stamp. It contains the shell's ver-
               sion number (see tcsh), origin, release date, ven-
               dor,  operating  system  and  machine (see VENDOR,
               OSTYPE and MACHTYPE) and a comma-separated list of
               options  which  were set at compile time.  Options
               which are set by default in the  distribution  are
               noted.

               8b  The shell is eight bit clean; default
               7b  The shell is not eight bit clean
               nls The  system's NLS is used; default for systems
                   with NLS
               lf  Login  shells  execute  /etc/csh.login  before
                   instead  of  after /etc/csh.cshrc and ~/.login
                   before instead of after ~/.tcshrc and  ~/.his-
                   tory.
               dl  `.' is put last in path for security; default
               nd  `.' is omitted from path for security
               vi  vi-style  editing  is  the default rather than
                   emacs
               dtr Login shells drop DTR when exiting
               bye bye is a synonym for  logout  and  log  is  an
                   alternate name for watchlog
               al  autologout is enabled; default
               kan Kanji  is  used  and  the ISO character set is
                   ignored, unless the nokanji shell variable  is
                   set
               sm  The system's malloc(3) is used
               hb  The  `#!<program>  <args>'  convention is emu-
                   lated when executing shell scripts
               ng  The newgrp builtin is available
               rh  The shell attempts to set the REMOTEHOST envi-
                   ronment variable
               afs The shell verifies your password with the ker-
                   beros server if  local  authentication  fails.
                   The  afsuser  shell  variable  or  the AFSUSER
                   environment variable override your local user-
                   name if set.

               An  administrator  may enter additional strings to
               indicate differences in the local version.

       visiblebell (+)
               If set, a screen flash is  used  rather  than  the
               audible bell.  See also nobeep.

       watch (+)
               A  list of user/terminal pairs to watch for logins
               and logouts.  If either the user is `any' all ter-
               minals  are  watched  for  the given user and vice
               versa.  Setting watch to `(any any)'  watches  all
               users and terminals.  For example,

                   set  watch  =  (george ttyd1 any console $user
                   any)

               reports activity of the user  `george'  on  ttyd1,
               any  user  on the console, and oneself (or a tres-
               passer) on any terminal.

               Logins and logouts are checked every 10 minutes by
               default, but the first word of watch can be set to
               a number to check  every  so  many  minutes.   For
               example,

                   set watch = (1 any any)

               reports  any  login/logout  once every minute. For
               the impatient, the log builtin command triggers  a
               watch  report  at any time. All current logins are
               reported (as with the log builtin) when  watch  is
               first set.

               The  who  shell  variable  controls  the format of
               watch reports.

       who (+) The format string for watch messages. The  follow-
               ing  sequences  are replaced by the given informa-
               tion:

               %n  The name of the user who logged in/out.
               %a  The observed action, i.e. `logged on', `logged
                   off' or `replaced olduser on'.
               %l  The  terminal  (tty)  on which the user logged
                   in/out.
               %M  The full  hostname  of  the  remote  host,  or
                   `local' if the login/logout was from the local
                   host.
               %m  The hostname of the  remote  host  up  to  the
                   first  `.'.  The full name is printed if it is
                   an IP address or an X Window System display.

               %M and %m are  available  only  on  systems  which
               store the remote hostname in /etc/utmp.  If unset,
               `%n has %a %l from %m.' is used,  or  `%n  has  %a
               %l.' on systems which don't store the remote host-
               name.

       wordchars (+)
               A list of non-alphanumeric characters to  be  con-
               sidered  part of a word by the forward-word, back-
               ward-word  etc.  editor   commands.    If   unset,
               `*?_-.[]~=' is used.

ENVIRONMENT
       AFSUSER (+)
               Equivalent to the afsuser shell variable.

       COLUMNS The  number of columns in the terminal. See Termi-
               nal management.

       DISPLAY Used by X Window System (see X(1)).  If  set,  the
               shell does not set autologout (q.v.).

       EDITOR  The  pathname  to  a default editor.  See also the
               VISUAL environment variable and the  run-fg-editor
               editor command.

       GROUP (+)
               Equivalent to the group shell variable.

       HOME    Equivalent to the home shell variable.

       HOST (+)
               Initialized  to  the  name of the machine on which
               the shell is running, as determined by  the  geth-
               ostname(2) system call.

       HOSTTYPE (+)
               Initialized  to  the  type of machine on which the
               shell is running, as determined at  compile  time.
               This variable is obsolete and will be removed in a
               future version.

       HPATH (+)
               A colon-separated list of directories in which the
               run-help editor command looks for command documen-
               tation.

       LANG    Gives the preferred  character  environment.   See
               Native Language System support.

       LC_CTYPE
               If  set, only ctype character handling is changed.
               See Native Language System support.

       LINES   The number of lines in the terminal. See  Terminal
               management.

       LS_COLORS
               The  format  of this variable is reminicent of the
               termcap(5) file format; a colon-separated list  of
               expressions of the form "xx=string", where "xx" is
               a two-character variable name.  The variables with
               their associated defaults are:

               no   0    Normal (non-filename) text
               fi   0    Regular file
               di   01;34     Directory
               ln   01;36     Symbolic link
               pi   33   Named pipe (FIFO)
               so   01;35     Socket
               bd   01;33     Block device
               cd   01;32     Character device
               ex   01;32     Executable file
               mi   (none)    Missing file (defaults to fi)
               or   (none)    Orphanned symbolic link (defaults to ln)
               lc   ^[[  Left code
               rc   m    Right code
               ec   (none)    End code (replaces lc+no+rc)

               You only need to include the variables you want to
               change from the default.

               File names can also be colorized based on filename
               extension.   This  is  specified  in the LS_COLORS
               variable  using  the  syntax  "*ext=string".   For
               example, using ISO 6429 codes, to color all C-lan-
               guage  source  files  blue   you   would   specify
               "*.c=34".  This would color all files ending in .c
               in blue (34) color.

               Control  characters  can  be  written  either   in
               C-style-escaped  notation, or in stty-like ^-nota-
               tion.  The C-style notation adds ^[ for Escape,  _
               for a normal space characer, and ? for Delete.  In
               addition, the ^[ escape character can be  used  to
               override  the  default  interpretation of ^[, ^, :
               and =.

               Each file will be  written  as  <lc>  <color-code>
               <rc>  <filename>  <ec>.  If the <ec> code is unde-
               fined, the sequence <lc> <no> <rc>  will  be  used
               instead.   This  is  generally  more convenient to
               use, but less general.  The left,  right  and  end
               codes  are provided so you don't have to type com-
               mon parts over and over again and to support weird
               terminals;  you  will generally not need to change
               them at all unless your terminal does not use  ISO
               6429 color sequences but a different system.

               If  your  terminal  does use ISO 6429 color codes,
               you can compose the type codes  (i.e.  all  except
               the  lc, rc, and ec codes) from numerical commands
               separated by semicolons.  The most common commands
               are:

                       0   to restore default color
                       1   for brighter colors
                       4   for underlined text
                       5   for flashing text
                       30  for black foreground
                       31  for red foreground
                       32  for green foreground
                       33  for yellow (or brown) foreground
                       34  for blue foreground
                       35  for purple foreground
                       36  for cyan foreground
                       37  for white (or gray) foreground
                       40  for black background
                       41  for red background
                       42  for green background
                       43  for yellow (or brown) background
                       44  for blue background
                       45  for purple background
                       46  for cyan background
                       47  for white (or gray) background
               Not  all commands will work on all systems or dis-
               play devices.
               A few  terminal  programs  do  not  recognize  the
               default  end code properly.  If all text gets col-
               orized after  you  do  a  directory  listing,  try
               changing the no and fi codes from 0 to the numeri-
               cal codes for your standard fore-  and  background
               colors.
       MACHTYPE (+)
               The  machine type (microprocessor class or machine
               model), as determined at compile time.
       NOREBIND (+)
               If set, printable characters are  not  rebound  to
               self-insert-command.   See  Native Language System
               support.
       OSTYPE (+)
               The operating system,  as  determined  at  compile
               time.
       PATH    A  colon-separated list of directories in which to
               look for  executables.   Equivalent  to  the  path
               shell variable, but in a different format.
       PWD (+) Equivalent to the cwd shell variable, but not syn-
               chronized to it;  updated  only  after  an  actual
               directory change.
       REMOTEHOST (+)
               The  host  from  which  the  user  has  logged  in
               remotely, if this is the case  and  the  shell  is
               able to determine it. Set only if the shell was so
               compiled; see the version shell variable.
       SHLVL (+)
               Equivalent to the shlvl shell variable.
       SYSTYPE (+)
               The current system type. (Domain/OS only)
       TERM    Equivalent to the term shell variable.
       TERMCAP The terminal capability string. See Terminal  man-
               agement.
       USER    Equivalent to the user shell variable.
       VENDOR (+)
               The vendor, as determined at compile time.
       VISUAL  The pathname to a default full-screen editor.  See
               also the EDITOR environment variable and the  run-
               fg-editor editor command.
FILES
       /etc/csh.cshrc  Read  first  by  every  shell.   ConvexOS,
                       Stellix and Intel use /etc/cshrc and NeXTs
                       use  /etc/cshrc.std.  A/UX, AMIX, Cray and
                       IRIX have no  equivalent  in  csh(1),  but
                       read  this  file  in tcsh anyway.  Solaris
                       2.x does not  have  it  either,  but  tcsh
                       reads /etc/.cshrc. (+)
       /etc/csh.login  Read by login shells after /etc/csh.cshrc.
                       ConvexOS,   Stellix    and    Intel    use
                       /etc/login,   NeXTs   use  /etc/login.std,
                       Solaris 2.x  uses  /etc/.login  and  A/UX,
                       AMIX, Cray and IRIX use /etc/cshrc.
       ~/.tcshrc (+)   Read  by  every shell after /etc/csh.cshrc
                       or its equivalent.
       ~/.cshrc        Read by every shell, if ~/.tcshrc  doesn't
                       exist, after /etc/csh.cshrc or its equiva-
                       lent.  This  manual  uses  `~/.tcshrc'  to
                       mean  `~/.tcshrc  or,  if ~/.tcshrc is not
                       found, ~/.cshrc'.
       ~/.history      Read by login shells  after  ~/.tcshrc  if
                       savehist is set, but see also histfile.
       ~/.login        Read  by  login  shells after ~/.tcshrc or
                       ~/.history.  The shell may be compiled  to
                       read  ~/.login  before  instead  of  after
                       ~/.tcshrc and ~/.history; see the  version
                       shell variable.
       ~/.cshdirs (+)  Read  by  login  shells  after ~/.login if
                       savedirs is set, but see also dirsfile.
       /etc/csh.logout Read by login shells at logout.  ConvexOS,
                       Stellix  and  Intel  use  /etc/logout  and
                       NeXTs use  /etc/logout.std.   A/UX,  AMIX,
                       Cray   and  IRIX  have  no  equivalent  in
                       csh(1), but read this file in tcsh anyway.
                       Solaris  2.x  does not have it either, but
                       tcsh reads /etc/.cshrc. (+)
       ~/.logout       Read  by  login  shells  at  logout  after
                       /etc/csh.logout or its equivalent.
       /bin/sh         Used to interpret shell scripts not start-
                       ing with a `#'.
       /tmp/sh*        Temporary file for `<<'.
       /etc/passwd     Source of  home  directories  for  `~name'
                       substitutions.

       The  order  in  which startup files are read may differ if
       the shell was so compiled; see Startup  and  shutdown  and
       the version shell variable.

NEW FEATURES (+)
       This manual describes tcsh as a single entity, but experi-
       enced csh(1) users will want to pay special  attention  to
       tcsh's new features.

       A   command-line  editor,  which  supports  GNU  Emacs  or
       vi(1)-style key bindings. See The command-line editor  and
       Editor commands.

       Programmable,  interactive  word  completion  and listing.
       See Completion and listing and the complete and uncomplete
       builtin commands.

       Spelling  correction  (q.v.)  of  filenames,  commands and
       variables.

       Editor commands (q.v.) which perform  other  useful  func-
       tions  in the middle of typed commands, including documen-
       tation lookup (run-help), quick editor restarting (run-fg-
       editor) and command resolution (which-command).

       An  enhanced history mechanism. Events in the history list
       are time-stamped.  See also the history  command  and  its
       associated  shell  variables,  the previously undocumented
       `#' event specifier and new modifiers under  History  sub-
       stitution,  the  *-history,  history-search-*, i-search-*,
       vi-search-* and toggle-literal-history editor commands and
       the histlit shell variable.

       Enhanced  directory  parsing and directory stack handling.
       See the cd, pushd, popd and dirs commands and their  asso-
       ciated shell variables, the description of Directory stack
       substitution, the dirstack, owd and symlinks  shell  vari-
       ables  and the normalize-command and normalize-path editor
       commands.

       Negation in glob-patterns. See Filename substitution.

       New File inquiry operators (q.v.) and a  filetest  builtin
       which uses them.

       A  variety  of Automatic, periodic and timed events (q.v.)
       including scheduled  events,  special  aliases,  automatic
       logout  and  terminal locking, command timing and watching
       for logins and logouts.

       Support for the Native Language System  (see  Native  Lan-
       guage System support), OS variant features (see OS variant
       support and the echo_style  shell  variable)  and  system-
       dependent file locations (see FILES).

       Extensive  terminal-managment  capabilities.  See Terminal
       management.

       New builtin commands including builtins, hup,  ls-F,  new-
       grp, printenv, which and where (q.v.).

       New  variables  that make useful information easily avail-
       able to the shell.  See  the  gid,  loginsh,  oid,  shlvl,
       tcsh,  tty,  uid and version shell variables and the HOST,
       REMOTEHOST, VENDOR, OSTYPE and MACHTYPE environment  vari-
       ables.

       A  new  syntax  for  including  useful  information in the
       prompt string (see prompt).  and special prompts for loops
       and spelling correction (see prompt2 and prompt3).

       Read-only variables. See Variable substitution.

BUGS
       When  a  suspended  command is restarted, the shell prints
       the directory it started in if this is different from  the
       current  directory. This can be misleading (i.e. wrong) as
       the job may have changed directories internally.

       Shell builtin  functions  are  not  stoppable/restartable.
       Command  sequences  of  the  form `a ; b ; c' are also not
       handled gracefully when stopping  is  attempted.   If  you
       suspend  `b', the shell will then immediately execute `c'.
       This is especially noticeable if  this  expansion  results
       from  an  alias. It suffices to place the sequence of com-
       mands in ()'s to force it to a subshell, i.e. `( a ; b ; c
       )'.

       Control  over  tty  output  after processes are started is
       primitive; perhaps this will inspire someone to work on  a
       good  virtual  terminal  interface.  In a virtual terminal
       interface much more interesting things could be done  with
       output control.

       Alias substitution is most often used to clumsily simulate
       shell procedures;  shell  procedures  should  be  provided
       rather than aliases.

       Commands  within loops are not placed in the history list.
       Control structures should be parsed rather than being rec-
       ognized  as  built-in  commands.  This would allow control
       commands to be placed anywhere, to be combined  with  `|',
       and to be used with `&' and `;' metasyntax.

       foreach doesn't ignore here documents when looking for its
       end.

       It should be possible to use the `:' modifiers on the out-
       put of command substitutions.

       The  screen  update for lines longer than the screen width
       is very poor if the terminal cannot  move  the  cursor  up
       (i.e. terminal type `dumb').

       HPATH and NOREBIND don't need to be environment variables.

       Glob-patterns which do not use `?', `*' or `[]'  or  which
       use `{}' or `~' are not negated correctly.

       The single-command form of if does output redirection even
       if the expression is false and the  command  is  not  exe-
       cuted.

       ls-F  includes file identification characters when sorting
       filenames and does not handle control characters in  file-
       names well. It cannot be interrupted.

       Report bugs to tcsh-bugs@mx.gw.com, preferably with fixes.
       If you want to help maintain and test tcsh, send  mail  to
       listserv@mx.gw.com  with  the  text  `subscribe tcsh <your
       name>' on a line by itself in the body. You can also `sub-
       scribe  tcsh-bugs  <your name>' to get all bug reports, or
       `subscribe tcsh-diffs <your name>' to get the  development
       list plus diffs for each patchlevel.

THE T IN TCSH
       In  1964,  DEC  produced the PDP-6. The PDP-10 was a later
       re-implementation. It was re-christened  the  DECsystem-10
       in  1970  or so when DEC brought out the second model, the
       KI10.

       TENEX was created at Bolt, Beranek & Newman (a  Cambridge,
       Mass. think tank) in 1972 as an experiment in demand-paged
       virtual memory operating systems. They built a  new  pager
       for  the  DEC  PDP-10 and created the OS to go with it. It
       was extremely successful in academia.

       In 1975, DEC brought out a new model of  the  PDP-10,  the
       KL10; they intended to have only a version of TENEX, which
       they had licensed from BBN, for the new box.  They  called
       their  version  TOPS-20  (their  capitalization  is trade-
       marked).  A lot of TOPS-10 users  (`The  OPerating  System
       for  PDP-10') objected; thus DEC found themselves support-
       ing two incompatible systems  on  the  same  hardware--but
       then there were 6 on the PDP-11!

       TENEX,  and  TOPS-20  to version 3, had command completion
       via a user-code-level subroutine  library  called  ULTCMD.
       With  version  3,  DEC  moved all that capability and more
       into the monitor (`kernel' for you Unix  types),  accessed
       by  the  COMND%  JSYS  (`Jump  to SYStem' instruction, the
       supervisor call mechanism [are my  IBM  roots  also  show-
       ing?]).

       The creator of tcsh was impressed by this feature and sev-
       eral others of TENEX and TOPS-20, and created a version of
       csh which mimicked them.

LIMITATIONS
       Words can be no longer than 1024 characters.

       The system limits argument lists to 10240 characters.

       The  number of arguments to a command which involves file-
       name expansion is limited to 1/6th the number  of  charac-
       ters allowed in an argument list.

       Command  substitutions  may  substitute no more characters
       than are allowed in an argument list.

       To detect looping, the shell restricts the number of alias
       substitutions on a single line to 20.

SEE ALSO
       csh(1),  emacs(1),  ls(1),  newgrp(1),  sh(1), setpath(1),
       stty(1),   su(1),   tset(1),   vi(1),   x(1),   access(2),
       execve(2),   fork(2),  killpg(2),  pipe(2),  setrlimit(2),
       sigvec(2),  stat(2),  umask(2),  vfork(2),  wait(2),  mal-
       loc(3),  setlocale(3), tty(4), a.out(5), termcap(5), envi-
       ron(7), termio(7), Introduction to the C Shell

VERSION
       This manual documents tcsh 6.08.00 (Astron) 1998-10-02.

AUTHORS
       William Joy
         Original author of csh(1)
       J.E. Kulp, IIASA, Laxenburg, Austria
         Job control and directory stack features
       Ken Greer, HP Labs, 1981
         File name completion
       Mike Ellis, Fairchild, 1983
         Command name recognition/completion
       Paul Placeway, Ohio State CIS Dept., 1983-1993
         Command line editor, prompt routines,  new  glob  syntax
         and numerous fixes and speedups
       Karl Kleinpaste, CCI 1983-4
         Special   aliases,  directory  stack  extraction  stuff,
         login/logout watch, scheduled events, and  the  idea  of
         the new prompt format
       Rayan Zachariassen, University of Toronto, 1984
         ls-F  and which builtins and numerous bug fixes, modifi-
         cations and speedups
       Chris Kingsley, Caltech
         Fast storage allocator routines
       Chris Grevstad, TRW, 1987
         Incorporated 4.3BSD csh into tcsh
       Christos S. Zoulas, Cornell U. EE Dept., 1987-94
         Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c,
         SHORT_STRINGS support and a new version of sh.glob.c
       James J Dempsey, BBN, and Paul Placeway, OSU, 1988
         A/UX port
       Daniel Long, NNSC, 1988
         wordchars
       Patrick Wolfe, Kuck and Associates, Inc., 1988
         vi mode cleanup
       David C Lawrence, Rensselaer Polytechnic Institute, 1989
         autolist and ambiguous completion listing
       Alec Wolman, DEC, 1989
         Newlines in the prompt
       Matt Landau, BBN, 1989
         ~/.tcshrc
       Ray Moody, Purdue Physics, 1989
         Magic spacebar history expansion
       Mordechai ????, Intel, 1989
         printprompt() fixes and additions
       Kazuhiro Honda, Dept. of Computer Science, Keio
         University, 1989
         Automatic spelling correction and prompt3
       Per Hedeland, Ellemtel, Sweden, 1990-
         Various bugfixes, improvements and manual updates
       Hans J. Albertsson (Sun Sweden)
         ampm, settc and telltc
       Michael Bloom
         Interrupt handling fixes
       Michael Fine, Digital Equipment Corp
         Extended key support
       Eric Schnoebelen, Convex, 1990
         Convex support, lots of csh bug fixes, save and  restore
         of directory stack
       Ron Flax, Apple, 1990
         A/UX 2.0 (re)port
       Dan Oscarsson, LTH Sweden, 1990
         NLS support and simulated NLS support for non NLS sites,
         fixes
       Johan Widen, SICS Sweden, 1990
         shlvl, Mach support, correct-line, 8-bit printing
       Matt Day, Sanyo Icon, 1990
         POSIX termio support, SysV limit fixes
       Jaap Vermeulen, Sequent, 1990-91
         Vi mode fixes, expand-line, window change fixes,  Symme-
         try port
       Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
         autolist beeping options, modified the history search to
         search for the whole string from the  beginning  of  the
         line to the cursor.
       Scott Krotz, Motorola, 1991
         Minix port
       David Dawes, Sydney U. Australia, Physics Dept., 1991
         SVR4 job control fixes
       Jose Sousa, Interactive Systems Corp., 1991
         Extended vi fixes and vi delete command
       Marc Horowitz, MIT, 1991
         ANSIfication  fixes, new exec hashing code, imake fixes,
         where
       Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
         ETA  and  Pyramid  port,  Makefile   and   lint   fixes,
         ignoreeof=n  addition,  and  various  other  portability
         changes and bug fixes
       Jeff Fink, 1992
         complete-word-fwd and complete-word-back
       Harry C. Pulley, 1992
         Coherent port
       Andy Phillips, Mullard Space Science Lab U.K., 1992
         VMS-POSIX port
       Beto Appleton, IBM Corp., 1992
         Walking process group fixes, csh bug fixes,  POSIX  file
         tests, POSIX SIGHUP
       Scott Bolte, Cray Computer Corp., 1992
         CSOS port
       Kaveh R. Ghazi, Rutgers University, 1992
         Tek,  m88k,  Titan  and  Masscomp ports and fixes. Added
         autoconf support.
       Mark Linderman, Cornell University, 1992
         OS/2 port
       Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
         Linux port
       Tim P. Starrin, NASA Langley Research Center Operations,
         1993
         Read-only variables
       Dave Schweisguth, Yale University, 1993-4
         New manpage and tcsh.man2html
       Larry Schwimmer, Stanford University, 1993
         AFS and HESIOD patches
       Luke Mewburn, RMIT University, 1994-6
         Enhanced  directory  printing  in prompt, added ellipsis
         and rprompt.
       Edward Hutchins, Silicon Graphics Inc., 1996
         Added implicit cd.
       Martin Kraemer, 1997
         Ported to Siemens Nixdorf EBCDIC machine
       Amol Deshpande, Microsoft, 1997
         Ported to WIN32 (Windows/95 and Windows/NT);  wrote  all
         the  missing  library and message catalog code to inter-
         face to Windows.
       Taga Nayuta, 1998
         Color ls additions.

THANKS TO
       Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson,
       Steve Romig, Diana Smetters, Bob Sutterfield, Mark Verber,
       Elizabeth Zwicky and all the other people  at  Ohio  State
       for suggestions and encouragement

       All  the people on the net, for putting up with, reporting
       bugs in, and suggesting new additions to  each  and  every
       version

       Richard  M. Alderson III, for writing the `T in tcsh' sec-
       tion

Astron 6.08.00            2 October 1998                        1