tset(1) 						      General Commands Manual							   tset(1)

NAME

       tset, reset - terminal initialization

SYNOPSIS

       tset [-IQVcqrsw] [-] [-e ch] [-i ch] [-k ch] [-m mapping] [terminal]
       reset [-IQVcqrsw] [-] [-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 the section TERMINAL TYPE MAPPING
       for more information).  Then, if the terminal type begins with a question mark (``?''), the user is prompted for confirmation of the termi-
       nal  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 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 initialization strings are sent to the standard error output.  Finally, if the erase, interrupt and line kill  charac-
       ters  have  changed,  or  are  not  set to their default values, their values are displayed to the standard error output.  Use the -c or -w
       option to select only the window sizing versus the other initialization.  If neither option is given, both are assumed.

       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 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:

       -c   Set control characters and modes.  -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 the section TERMINAL TYPE MAPPING for more information.

       -Q   Do not display any values for the erase, interrupt and line kill characters.  Normally tset displays the values for control characters
	    which differ from the system's default values.

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

       -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 SETTING THE
	    ENVIRONMENT for details.

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

       -w   Resize the window to match the size deduced via setupterm.	Normally this has no effect, unless setupterm is not able  to  detect  the
	    window size.

       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 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 cor-
       rectly:

	   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  out-
       put (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 applicable 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 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  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
       exclamation marks (``!'').

HISTORY

       The tset command appeared in BSD 3.0.  The ncurses implementation was lightly adapted from the 4.4BSD sources for a terminfo environment by
       Eric S. Raymond <esr@snark.thyrsus.com>.

COMPATIBILITY

       The  tset  utility  has been provided for backward-compatibility 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 beginning 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 lim-
       ited  utility  at best.	The -a, -d, and -p options are similarly not documented or useful, but were retained as they appear to be in wide-
       spread 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 recommended 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  argu-
       ment in some historic implementations of tset has been removed.

ENVIRONMENT

       The tset command uses these environment variables:

       SHELL
	    tells tset whether to initialize TERM using sh or csh syntax.

       TERM Denotes your terminal type.  Each terminal type is distinct, though many are similar.

       TERMCAP
	    may  denote the location of a termcap database.  If it is not an absolute pathname, e.g., begins with a `/', tset removes the variable
	    from the environment before looking for the terminal description.

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), curs_terminfo(3X), tty(4), terminfo(5), ttys(5), environ(7)

       This describes ncurses version 5.7 (patch 20081102).

																	   tset(1)