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TSET(1)			  BSD General Commands Manual		       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, us-
     ing 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 de-
	       vice 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.

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

     -Q	   Do not display any values for the erase, interrupt and line kill
	   characters.

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

     -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 ac-
     tual 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 desir-
     able 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 condi-
     tions 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 op-
     tional 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 compared with	the
     speed of the standard error output	(which should be the control termi-
     nal).  The	terminal type is a string.

     If	the terminal type is not specified on the command line,	the -m map-
     pings 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 ap-
     plicable 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 port	type is	specified, the terminal	type will match	any port type,
     for example, "-m dialup:vt100 -m :?xterm" will cause any dialup port, re-
     gardless 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

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 in-
     teraction between the - option and	the terminal argument in some historic
     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") compli-
     ant terminal interface) and will no longer	compile	on systems with	older
     terminal interfaces.

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

HISTORY
     The tset command appeared in 3.0BSD.

BSD				 June 9, 1993				   BSD

NAME | SYNOPSIS | DESCRIPTION | SETTING THE ENVIRONMENT | TERMINAL TYPE MAPPING | ENVIRONMENT | FILES | COMPATIBILITY | SEE ALSO | HISTORY

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