tset(1)                                                   tset(1)

NAME
       tset - terminal initialization

SYNOPSIS
       tset  [-IQqrs]  [-]  [-e  ch] [-i ch] [-k ch] [-m mapping]
       [terminal]
       reset [-IQqrs] [-] [-e ch] [-i ch] [-k  ch]  [-m  mapping]
       [terminal]

DESCRIPTION
       Tset  initializes  terminals.   Tset  first determines the
       type of terminal that you are using.   This  determination
       is done as follows, using the first terminal type found.

       1. The terminal argument specified on the command line.

       2. The value of the TERM environmental variable.

       3.  (BSD  systems only.) The terminal type associated with
       the standard error output device in  the  /etc/ttys  file.
       (On Linux and System-V-like UNIXes, getty does this job by
       setting TERM  according  to  the  type  passed  to  it  by
       /etc/inittab.)

       4. The default terminal type, ``unknown''.

       If  the  terminal  type  was not specified on the command-
       line, the -m option mappings are then applied  (see  below
       for  more information).  Then, if the terminal type begins
       with a question mark (``?''), the  user  is  prompted  for
       confirmation of the terminal type.  An empty response con-
       firms the type, or, another type can be entered to specify
       a  new  type.  Once the terminal type has been determined,
       the terminfo entry for the terminal is retrieved.   If  no
       terminfo entry is found for the type, the user is prompted
       for another terminal type.

       Once the terminfo entry is  retrieved,  the  window  size,
       backspace,  interrupt and line kill characters (among many
       other things) are set and the terminal and tab initializa-
       tion  strings  are  sent  to  the  standard  error output.
       Finally, if the erase, interrupt and line kill  characters
       have  changed,  or  are  not  set to their default values,
       their values are displayed to the standard error output.

       When invoked as reset, tset sets cooked  and  echo  modes,
       turns  off cbreak and raw modes, turns on newline transla-
       tion and resets any  unset  special  characters  to  their
       default  values  before  doing the terminal initialization
       described above.  This is  useful  after  a  program  dies
       leaving  a  terminal  in an abnormal state.  Note, you may
       have to type

           <LF>reset<LF>

       (the line-feed character is normally control-J) to get the
       terminal to work, as carriage-return may no longer work in
       the abnormal state.  Also, the  terminal  will  often  not
       echo the command.

       The options are as follows:

       -q   The  terminal  type is displayed to the standard out-
            put, and the terminal is not initialized in any  way.
            The option `-' by itself is equivalent but archaic.

       -e   Set the erase character to ch.

       -I   Do  not  send  the  terminal  or  tab  initialization
            strings to the terminal.

       -i   Set the interrupt character to ch.

       -k   Set the line kill character to ch.

       -m   Specify a mapping from a port  type  to  a  terminal.
            See below for more information.

       -Q   Don't display any values for the erase, interrupt and
            line kill characters.

       -r   Print the terminal type to the standard error output.

       -s   Print  the  sequence  of shell commands to initialize
            the environment variable TERM to the standard output.
            See  the section below on setting the environment for
            details.

       The arguments for the -e, -i, and -k options may either be
       entered  as  actual characters or by using the `hat' nota-
       tion, i.e. control-h may be specified as ``^H'' or ``^h''.

SETTING THE ENVIRONMENT
       It  is  often  desirable  to  enter  the terminal type and
       information about the  terminal's  capabilities  into  the
       shell's environment.  This is done using the -s option.

       When the -s option is specified, the commands to enter the
       information into the shell's environment  are  written  to
       the  standard output.  If the SHELL environmental variable
       ends in ``csh'', the commands are for csh, otherwise, they
       are  for  sh.   Note,  the  csh commands set and unset the
       shell variable noglob, leaving it  unset.   The  following
       line  in  the .login or .profile files will initialize the
       environment correctly:

           eval `tset -s options ... `

TERMINAL TYPE MAPPING
       When the terminal is not hardwired into the system (or the
       current system information is incorrect) the terminal type
       derived from the /etc/ttys file or the TERM  environmental
       variable  is often something generic like network, dialup,
       or unknown.  When tset is used in a startup script  it  is
       often  desirable  to provide information about the type of
       terminal used on such ports.

       The purpose of the -m option is to map from  some  set  of
       conditions  to a terminal type, that is, to tell tset ``If
       I'm on this port at a particular speed, guess that I'm  on
       that kind of terminal''.

       The argument to the -m option consists of an optional port
       type, an optional operator, an optional baud rate specifi-
       cation, an optional colon (``:'') character and a terminal
       type.  The port type is a string (delimited by either  the
       operator or the colon character).  The operator may be any
       combination of ``>'', ``<'', ``@'', and ``!''; ``>'' means
       greater  than, ``<'' means less than, ``@'' means equal to
       and ``!'' inverts the sense of the test.  The baud rate is
       specified  as  a  number and is compared with the speed of
       the standard error output (which  should  be  the  control
       terminal).  The terminal type is a string.

       If the terminal type is not specified on the command line,
       the -m mappings are applied to the terminal type.  If  the
       port  type  and  baud rate match the mapping, the terminal
       type specified in the mapping replaces the  current  type.
       If  more than one mapping is specified, the first applica-
       ble mapping is used.

       For   example,    consider    the    following    mapping:
       dialup>9600:vt100.  The port type is dialup , the operator
       is >, the baud rate specification is 9600, and the  termi-
       nal type is vt100.  The result of this mapping is to spec-
       ify that if the terminal type is dialup, and the baud rate
       is  greater  than 9600 baud, a terminal type of vt100 will
       be used.

       If no baud rate is specified, the terminal type will match
       any baud rate.  If no port type is specified, the terminal
       type  will  match  any  port  type.    For   example,   -m
       dialup:vt100  -m  :?xterm  will  cause  any  dialup  port,
       regardless of baud rate, to match the terminal type vt100,
       and  any  non-dialup  port type to match the terminal type
       ?xterm.  Note, because of the leading question  mark,  the
       user  will be queried on a default port as to whether they
       are actually using an xterm terminal.

       No whitespace characters are permitted in  the  -m  option
       argument.   Also,  to avoid problems with meta-characters,
       it is suggested that the  entire  -m  option  argument  be
       placed  within single quote characters, and that csh users
       insert a backslash character (``\'') before  any  exclama-
       tion marks (``!'').

HISTORY
       The  tset command appeared in BSD 3.0.  The ncurses imple-
       mentation was lightly adapted from the 4.4BSD sources  for
       a terminfo environment by Eric S. Raymond <esr@snark.thyr-
       sus.com>.

COMPATIBILITY
       The tset utility has been provided  for  backward-compati-
       bility  with  BSD  environments (under most modern UNIXes,
       /etc/inittab and getty(1) can set TERM  appropriately  for
       each  dial-up  line;  this  obviates  what was tset's most
       important use).  This implementation behaves  like  4.4BSD
       tset, with a few exceptions specified here.

       The  -S  option  of BSD tset no longer works; it prints an
       error message to stderr and dies.  The -s option only sets
       TERM,  not  TERMCAP.   Both  these changes are because the
       TERMCAP variable is no longer  supported  under  terminfo-
       based ncurses, which makes tset -S useless (we made it die
       noisily rather than silently induce lossage).

       There was an undocumented  4.4BSD  feature  that  invoking
       tset via a link named `TSET` (or via any other name begin-
       ning with an upper-case letter) set the  terminal  to  use
       upper-case only.  This feature has been omitted.

       The  -A,  -E,  -h, -u and -v options were deleted from the
       tset utility in 4.4BSD. None of them  were  documented  in
       4.3BSD and all are of limited utility at best. The -a, -d,
       and -p options are similarly not documented or useful, but
       were  retained as they appear to be in widespread use.  It
       is strongly recommended that  any  usage  of  these  three
       options  be  changed to use the -m option instead.  The -n
       option remains, but has no effect.  The -adnp options  are
       therefore omitted from the usage summary above.

       It  is  still  permissible  to  specify the -e, -i, and -k
       options without arguments, although it is strongly  recom-
       mended  that such usage be fixed to explicitly specify the
       character.

       As of 4.4BSD, executing tset as reset  no  longer  implies
       the -Q option.  Also, the interaction between the - option
       and the terminal argument in some historic implementations
       of tset has been removed.

ENVIRONMENT
       The tset command uses the SHELL and TERM environment vari-
       ables.

FILES
       /etc/ttys
            system port name to terminal  type  mapping  database
            (BSD versions only).

       /usr/share/terminfo
            terminal capability database

SEE ALSO
       csh(1), sh(1), stty(1), tty(4), termcap(5), ttys(5), envi-
       ron(7)

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