# tset 1

    tset(1)                                                   tset(1)

## NAME

           tset, reset - terminal initialization

## SYNOPSIS

           tset  [-IQVqrs]  [-]  [-e ch] [-i ch] [-k ch] [-m mapping]
           [terminal]
           reset [-IQVqrs] [-] [-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.

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

           -V   reports the version of ncurses which was used in this
                program, and exits.

           -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.

           -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
           specification, 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, -,
           and                                                      -
           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 there-
           fore 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)

                                                              tset(1)