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tset(1)

NAME

     tset, reset -- terminal initialization

SYNOPSIS

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

DESCRIPTION

     The tset utility initializes terminals.  It first determines the type of
     terminal that you are using.  This determination is done as follows,
     using the first terminal type found.

	   o   The terminal argument specified on the command line.
	   o   The value of the TERM environment variable.
	   o   The terminal type associated with the standard error output
	       device in the /etc/ttys file.
	   o   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 confirms the
     type, or, another type can be entered to specify a new type.  Once the
     terminal type has been determined, the termcap entry for the terminal is
     retrieved.  If no termcap entry is found for the type, the user is
     prompted for another terminal type.

     Once the termcap entry is retrieved, the window size, backspace, inter-
     rupt and line kill characters (among many other things) are set and the
     terminal and tab initialization 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 dis-
     played to the standard error output.

     When invoked as reset, tset sets cooked and echo modes, turns off cbreak
     and raw modes, turns on newline translation and resets any unset special
     characters to their default values before doing the terminal initializa-
     tion described above.  This is useful after a program dies leaving a ter-
     minal 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:

     -	   The terminal type is displayed to the standard output, and the ter-
	   minal is not initialized in any way.

     -e    Set the erase character to ch.

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

     -i    Set the interrupt character to ch.

     -k    Set the line kill character to ch.

     -S    Print the terminal type and the termcap entry to the standard out-
	   put.  See the section below on setting the environment for details.

     -s    Print the sequence of shell commands to initialize the environment
	   variables TERM and TERMCAP 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'' notation, 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 and -s options.

     When the -S option is specified, the terminal type and the termcap entry
     are written to the standard output, separated by a space and without a
     terminating newline.  This can be assigned to an array by csh and ksh
     users and then used like any other shell array.

     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 environment variable ends in ``csh'', the commands are for the csh,
     otherwise, they are for sh(1).  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 ... `

     To demonstrate a simple use of the -S option, the following lines in the
     .login file have an equivalent effect:

	   set noglob
	   set term=(`tset -S options ...`)
	   setenv TERM $term[1]
	   setenv TERMCAP "$term[2]"
	   unset term
	   unset noglob

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 environment variable is often something generic like
     ``network'', ``dialup'', or ``unknown''.  When tset is used in a startup
     script (.profile for sh(1) users or .login for csh(1) users) 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 con-
     ditions 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 (delim-
     ited 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 com-

     For example, consider the following mapping: ``dialup>9600:vt100''.  The
     port type is ``dialup'', the operator is ``>'', the baud rate specifica-
     tion is ``9600'', and the terminal type is ``vt100''.  The result of this
     mapping is to specify 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 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 metacharacters, 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 exclamation marks
     (``!'').

ENVIRONMENT

     The tset command utilizes the SHELL and TERM environment variables.

FILES

     /etc/ttys		      system port name to terminal type mapping data-
			      base
     /usr/share/misc/termcap  terminal capability database

SEE ALSO

     csh(1), sh(1), stty(1), tty(4), termcap(5), ttys(5), environ(7)

HISTORY

     The tset command appeared in 3.0BSD.

COMPATIBILITY

     The -A, -E, -h, -u and -v options have been deleted from the tset util-
     ity.  None of them were documented in 4.3BSD and all are of limited util-
     ity 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.  It
     is still permissible to specify the -e, -i and -k options without argu-
     ments, although it is strongly recommended that such usage be fixed to
     explicitly specify the character.

     Executing tset as reset no longer implies the -Q option.  Also, the
     interaction between the - option and the terminal argument in some his-
     toric implementations of tset has been removed.

     Finally, the tset implementation has been completely redone (as part of
     the addition to the system of a IEEE Std 1003.1-1988 (``POSIX.1'') com-
     pliant terminal interface) and will no longer compile on systems with
     older terminal interfaces.

FreeBSD 5.4			 June 9, 1993			   FreeBSD 5.4

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