ED(1)                        UNIX Reference Manual                       ED(1)

NAME
     ed - text editor

SYNOPSIS
     ed [-] [-sx] [-p string] [file]

DESCRIPTION
     Ed is a line-oriented text editor.  It is used to create, display, modify
     and otherwise manipulate text files.

     If invoked with a file argument, then a copy of file is read into the ed-
     itor's buffer.  Changes are made to this copy and not directly to file
     itself.  Upon quitting ed, any changes not explicitly saved  with a w
     command are lost.

     Editing is done in two distinct modes: command and input. When first in-
     voked, ed is in command mode.  In this mode commands are read from the
     standard input and executed to manipulate the contents of the editor
     buffer.  A typical command might look like:

     ,s/old/new/g

     which replaces all occurrences of the string old with new.

     When an input command, such as a (append), i (insert) or c (change), is
     given, ed enters input mode.  This is the primary means of adding text to
     a file.  In this mode, no commands are available; instead, the standard
     input is written directly to the editor buffer.  Lines consist of text up
     to and including a newline character.  Input mode is terminated by enter-
     ing a single period (.) on a line.

     All ed commands operate on whole lines or ranges of lines; e.g., the d
     command deletes lines; the m command moves lines, and so on.  It is pos-
     sible to modify only a portion of a line by means of replacement, as in
     the example above.  However even here, the s command is applied to whole
     lines at a time.

     In general, ed commands consist of zero or more line addresses, followed
     by a single character command and possibly additional parameters; i.e.,
     commands have the structure:

     [address [,address]]command[parameters]

     The address(es) indicate the line or range of lines to be affected by the
     command.  If fewer addresses are given than the command accepts, then de-
     fault addresses are supplied.

OPTIONS
     The following options are available:

     -s      Suppress diagnostics. This should be used if ed's standard input
             is from a script.

     -x      Prompt for an encryption key to be used in subsequent reads and
             writes (see the x command).

     -p string
             Specify a command prompt.  This may be toggled on and off with
             the P command.

     file    Specify the name of a file to read.  If file is prefixed with a
             bang (!), then it is interpreted as a shell command.  In this
             case, what is read is the standard output of file executed via
             sh(1).  To read a file whose name begins with a bang, prefix the
             name with a backslash (\).  The default filename is set to file
             only if it is not prefixed with a bang.

LINE ADDRESSING
     An address represents the number of a line in the buffer.  Ed maintains a
     current address which is typically supplied to commands as the default
     address when none is specified.  When a file is first read,  the current
     address is set to the last line of the file.  In general, the current ad-
     dress is set to the last line affected by a command.

     A line address is constructed from one of the bases in the list below,
     optionally followed by a numeric offset.  The offset may include any com-
     bination of digits, operators (i.e., +, - and ^) and whitespace.  Ad-
     dresses are read from left to right, and their values are computed rela-
     tive to the current address.

     One exception to the rule that addresses represent line numbers is the
     address 0 (zero).  This means "before the first line," and is legal wher-
     ever it makes sense.

     An address range is two addresses separated either by a comma or semi-
     colon. The value of the first address in a range cannot exceed the value
     of the second.  If only one address is given in a range, then the second
     address is set to the given address.  If an n-tuple of addresses is given
     where n > 2, then the corresponding range is determined by the last two
     addresses in the n-tuple. If only one address is expected, then the last
     address is used.

     Each address in a comma-delimited range is interpreted relative to the
     current address.  In a semi-colon-delimited range, the first address is
     used to set the current address, and the second address is interpreted
     relative to the first.

     The following address symbols are recognized:

     .       The current line (address) in the buffer.

     $       The last line in the buffer.

     n       The nth, line in the buffer where n is a number in the range
             [0,$].

     - or ^  The previous line.  This is equivalent to -1 and may be repeated
             with cumulative effect.

     -n or ^n
             The nth previous line, where n is a non-negative number.

     +       The next line.  This is equivalent to +1 and may be repeated with
             cumulative effect.

     +n      The nth next line, where n is a non-negative number.

     , or %  The first through last lines in the buffer.  This is equivalent
             to the address range 1,$.

     ;       The current through last lines in the buffer.  This is equivalent
             to the address range .,$.

     /re/    The next line containing the regular expression re. The search
             wraps to the beginning of the buffer and continues down to the
             current line, if necessary.  // repeats the last search.

     ?re?    The previous line containing the regular expression re. The
             search wraps to the end of the buffer and continues up to the
             current line, if necessary.  ?? repeats the last search.

     'lc     The line previously marked by a k (mark) command, where lc is a
             lower case letter.

REGULAR EXPRESSIONS
     Regular expressions are patterns used in selecting text.  For example,
     the command:

     g/string/

     prints all lines containing string. Regular expressions are also used by
     the s command for selecting old text to be replaced with new.

     In addition to a specifying string literals, regular expressions can rep-
     resent classes of strings.  Strings thus represented are said to be
     matched by the corresponding regular expression.  If it is possible for a
     regular expression to match several strings in a line, then the left-most
     longest match is the one selected.

     The following symbols are used in constructing regular expressions:

     c       Any character c not listed below, including `{', '}', `(', `)',
             `<' and `>', matches itself.

     \c      Any backslash-escaped character c, except for `{', '}', `(', `)',
             `<' and `>', matches itself.

     .       Match any single character.

     [char-class]
             Match any single character in char-class. To include a  `]' in
             char-class, it must be the first character.  A range of charac-
             ters may be specified by separating the end characters of the
             range with a `-', e.g., `a-z' specifies the lower case charac-
             ters.  The following literal expressions can also be used in
             char-class to specify sets of characters:

               [:alnum:]  [:cntrl:]  [:lower:]  [:space:]
               [:alpha:]  [:digit:]  [:print:]  [:upper:]
               [:blank:]  [:graph:]  [:punct:]  [:xdigit:]

             If `-' appears as the first or last character of char-class, then
             it matches itself.  All other characters in char-class match
             themselves.

             Patterns in char-class of the form:

               [.col-elm.] or,   [=col-elm=]

             where col-elm is a collating element are interpreted according to
             locale(5) (not currently supported).  See regex(3) for an expla-
             nation of these constructs.

     [^char-class]
             Match any single character, other than newline, not in char-
             class. Char-class is defined as above.

     ^       If ^ is the first character of a regular expression, then it an-
             chors the regular expression to the beginning of a line.  Other-
             wise, it matches itself.

     $       If $ is the last character of a regular expression, it anchors
             the regular expression to the end of a line.  Otherwise, it
             matches itself.

     \<      Anchor the single character regular expression or subexpression
             immediately following it to the beginning of a word.  (This may
             not be available)

     \>      Anchor the single character regular expression or subexpression
             immediately following it to the end of a word.  (This may not be
             available)

     \(re\)  Define a subexpression re. Subexpressions may be nested.  A sub-
             sequent backreference of the form \n, where n is a number in the
             range [1,9], expands to the text matched by the nth subexpres-
             sion.  For example, the regular expression `\(.*\)\1' matches any
             string consisting of identical adjacent substrings.  Subexpres-
             sions are ordered relative to their left delimiter.

     *       Match the single character regular expression or subexpression
             immediately preceding it zero or more times.  If * is the first
             character of a regular expression or subexpression, then it
             matches itself.  The * operator sometimes yields unexpected re-
             sults.  For example, the regular expression `b*' matches the be-
             ginning of the string `abbb' (as opposed to the substring `bbb'),
             since a null match is the only left-most match.

     \{n,m\} or \{n,\} or \{n\}
             Match the single character regular expression or subexpression
             immediately preceding it at least n and at most m times.  If m is
             omitted, then it matches at least n times.  If the comma is also
             omitted, then it matches exactly n times.

     Additional regular expression operators may be defined depending on the
     particular regex(3) implementation.

COMMANDS
     All ed commands are single characters, though some require additional pa-
     rameters.  If a command's parameters extend over several lines, then each
     line except for the last must be terminated with a backslash (\).

     In general, at most one command is allowed per line.  However, most com-
     mands accept a print suffix, which is any of p (print), l (list) , or n
     (enumerate), to print the last line affected by the command.

     An interrupt (typically ^C) has the effect of aborting the current com-
     mand and returning the editor to command mode.

     Ed recognizes the following commands.  The commands are shown together
     with the default address or address range supplied if none is specified
     (in parenthesis).

     (.)a    Append text to the buffer after the addressed line.  Text is en-
             tered in input mode.  The current address is set to last line en-
             tered.

     (.,.)c  Change lines in the buffer.  The addressed lines are deleted from
             the buffer, and text is appended in their place.  Text is entered
             in input mode.  The current address is set to last line entered.

     (.,.)d  Delete the addressed lines from the buffer.  If there is a line
             after the deleted range, then the current address is set to this
             line. Otherwise the current address is set to the line before the
             deleted range.

     e file  Edit file, and sets the default filename.  If file is not speci-
             fied, then the  default filename is used.  Any lines in the
             buffer are deleted before the new file is read.  The current ad-
             dress is set to the last line read.

     e !command
             Edit the standard output of !command, (see !command below).  The
             default filename is unchanged.  Any lines in the buffer are
             deleted before the output of command is read.  The current ad-
             dress is set to the last line read.

     E file  Edit file unconditionally.  This is similar to the e command, ex-
             cept that unwritten changes are discarded without warning.  The
             current address is set to the last line read.

     f file  Set the default filename to file. If file is not specified, then
             the default unescaped filename is printed.

     (1,$)g/re/command-list
             Apply command-list to each of the addressed lines matching a reg-
             ular expression re. The current address is set to the line cur-
             rently matched before command-list is executed.  At the end of
             the g command, the current address is set to the last line af-
             fected by command-list.

             Each command in command-list must be on a separate line, and ev-
             ery line except for the last must be terminated by a backslash
             (\).  Any commands are allowed, except for g, G, v, and V. A new-
             line alone in command-list is equivalent to a p command.

     (1,$)G/re/
             Interactively edit the addressed lines matching a regular expres-
             sion re. For each matching line, the line is printed, the current
             address is set, and the user is prompted to enter a command-list.
             At the end of the G command, the current address is set to the
             last line affected by (the last) command-list.

             The format of command-list is the same as that of the g command.
             A newline alone acts as a null command list.  A single `&' re-
             peats the last non-null command list.

     H       Toggle the printing of error explanations.  By default, explana-
             tions are not printed.  It is recommended that ed scripts begin
             with this command to aid in debugging.

     h       Print an explanation of the last error.

     (.)i    Insert text in the buffer before the current line.  Text is en-
             tered in input mode.  The current address is set to the last line
             entered.

     (.,.+1)j
             Join the addressed lines.  The addressed lines are deleted from
             the buffer and replaced by a single line containing their joined
             text.  The current address is set to the resultant line.

     (.)klc  Mark a line with a lower case letter lc. The  line can then be
             addressed as 'lc (i.e., a single quote followed by lc ) in subse-
             quent commands.  The mark is not cleared until the line is delet-
             ed or otherwise modified.

     (.,.)l  Print the addressed lines unambiguously.  If a single line fills
             for than one screen (as might be the case when viewing a binary
             file, for instance), a `--More--' prompt is printed on the last
             line.  Ed waits until the RETURN key is pressed before displaying
             the next screen.  The current address is set to the last line
             printed.

     (.,.)m(.)
             Move lines in the buffer.  The addressed lines are moved to after
             the right-hand destination address, which may be the address 0
             (zero).  The current address is set to the last line moved.

     (.,.)n  Print the addressed lines along with their line numbers.  The
             current address is set to the last line printed.

     (.,.)p  Print the addressed lines. The current address is set to the last
             line printed.

     P       Toggle the command prompt on and off.  Unless a prompt was speci-
             fied by with command-line option -p string, the command prompt is
             by default turned off.

     q       Quit ed.

     Q       Quit ed unconditionally.  This is similar to the q command, ex-
             cept that unwritten changes are discarded without warning.

     ($)r file
             Read file to after the addressed line.  If file is not specified,
             then the default filename is used.  If there was no default file-
             name prior to the command, then the default filename is set to
             file. Otherwise, the default filename is unchanged.  The current
             address is set to the last line read.

     ($)r !command
             Read to after the addressed line the standard output of !command,
             (see the !command below).  The default filename is unchanged.
             The current address is set to the last line read.

     (.,.)s/re/replacement/

     (.,.)s/re/replacement/g

     (.,.)s/re/replacement/n
             Replace text in the addressed lines matching a regular expression
             re with replacement. By default, only the first match in each
             line is replaced.  If the g (global) suffix is given, then every
             match to be replaced.  The n suffix, where n is a positive num-
             ber, causes only the nth match to be replaced.  It is an error if
             no substitutions are performed on any of the addressed lines.
             The current address is set the last line affected.

             Re and replacement may be delimited by any character other than
             space and newline (see the s command below).  If one or two of
             the last delimiters is omitted, then the last line affected is
             printed as though the print suffix p were specified.

             An unescaped `&' in replacement is replaced by the currently
             matched text.  The character sequence \m, where m is a number in
             the range [1,9], is replaced by the m th backreference expression
             of the matched text.  If replacement consists of a single `%',
             then replacement from the last substitution is used.  Newlines
             may be embedded in replacement if they are escaped with a back-
             slash (\).

     (.,.)s  Repeat the last substitution.  This form of the s command accepts
             a count suffix n, or any combination of the characters r, g, and
             p. If a count suffix n is given, then only the nth match is re-
             placed.  The r suffix causes the regular expression of the last
             search to be used instead of the that of the last substitution.
             The g suffix toggles the global suffix of the last substitution.
             The p suffix toggles the print suffix of the last substitution
             The current address is set to the last line affected.

     (.,.)t(.)
             Copy (i.e., transfer) the addressed lines to after the right-hand
             destination address, which may be the address 0 (zero).  The cur-
             rent address is set to the last line copied.

     u       Undo the last command and restores the current address to what it
             was before the command.  The global commands g, G, v, and V. are
             treated as a single command by undo.  u is its own inverse.

     (1,$)v/re/command-list
             Apply command-list to each of the addressed lines not matching a
             regular expression re. This is similar to the g command.

     (1,$)V/re/
             Interactively edit the addressed lines not matching a regular ex-
             pression re. This is similar to the G command.

     (1,$)w file
             Write the addressed lines to file. Any previous contents of file
             is lost without warning.  If there is no default filename, then
             the default filename is set to file, otherwise it is unchanged.
             If no filename is specified, then the default filename is used.
             The current address is unchanged.

     (1,$)wq file
             Write the addressed lines to file, and then executes a q command.

     (1,$)w !command
             Write the addressed lines to the standard input of !command, (see
             the !command below).  The default filename and current address
             are unchanged.

     (1,$)W file
             Append the addressed lines to the end of file. This is similar to
             the w command, expect that the previous contents of file is not
             clobbered.  The current address is unchanged.

     x       Prompt for an encryption key which is used in subsequent reads
             and writes.  If a newline alone is entered as the key, then en-
             cryption is turned off.  Otherwise, echoing is disabled while a
             key is read.  Encryption/decryption is done using the bdes(1) al-
             gorithm.

     (.+1)zn
             Scroll n lines at a time starting at addressed line.  If n is not
             specified, then the current window size is used.  The current ad-
             dress is set to the last line printed.

     !command
             Execute command via sh(1).  If the first character of command is
             `!', then it is replaced by text of the previous !command. Ed
             does not process command for backslash (\) escapes.  However, an
             unescaped % is replaced by the default filename.  When the shell
             returns from execution, a `!'  is printed to the standard output.
             The current line is unchanged.

     ($)=    Print the line number of the addressed line.

     (.+1)newline
             Print the addressed line, and sets the current address to that
             line.

FILES
     /tmp/ed.*  buffer file
     ed.hup     the file to which ed attempts to write the  buffer if the ter-
                minal hangs up

SEE ALSO
     bdes(1),  sed(1),  sh(1),  vi(1),  regex(3)

     USD:12-13

     B. W. Kernighan and P. J. Plauger, Software Tools in Pascal, 1981,
     Addison-Wesley.

LIMITATIONS
     Ed processes file arguments for backslash escapes, i.e.,  in a filename,
     any characters preceded by a backslash (\) are interpreted literally.

     If a text (non-binary) file is not terminated by a newline character,
     then ed appends one on reading/writing it.  In the case of a binary file,
     ed does not append a newline on reading/writing.

     per line overhead: 4 ints

DIAGNOSTICS
     When an error occurs, ed prints a `?' and either returns to command mode
     or exits if its input is from a script.  An explanation of the last error
     can be printed with the h (help) command.

     Since the g (global) command  masks any errors from failed searches and
     substitutions, it can be used to perform conditional operations in
     scripts; e.g.,

     g/old/s//new/

     replaces any occurrences of old with new. If the u (undo) command occurs
     in a global command list, then the command list is executed only once.

     If diagnostics are not disabled, attempting to quit ed or edit another
     file before writing a modified buffer results in an error.  If the com-
     mand is entered a second time, it succeeds, but any changes to the buffer
     are lost.

HISTORY
     A ed command appeared in Version 1 AT&T UNIX.

BSD Experimental                 May 21, 1993                                1