TSET(1) 						      General Commands Manual							   TSET(1)

NAME

       tset - terminal dependent initialization

SYNOPSIS

       tset [ options ] [ -m [ident][test baudrate]:type ] ... [ type ]

       reset [ options ] [ -m [ident][test baudrate]:type ] ... [ type ]

DESCRIPTION

       Tset  sets  up  your terminal when you first log in to a UNIX system.  It does terminal dependent processing such as setting erase and kill
       characters, setting or resetting delays, sending any sequences needed to properly initialized the terminal, and the like.  It first  deter-
       mines the type of terminal involved, and then does necessary initializations and mode settings.	The type of terminal attached to each UNIX
       port is specified in the /etc/ttys(5) database.	Type names for terminals may be found in the termcap(5) database.  If a port is not  wired
       permanently to a specific terminal (not hardwired) it will be given an appropriate generic identifier such as dialup.

       In  the	case where no arguments are specified, tset simply reads the terminal type out of the environment variable TERM and re-initializes
       the terminal.  The rest of this manual concerns itself with mode and environment initialization, typically done once at login, and  options
       used at initialization time to determine the terminal type and set up terminal modes.

       When  used  in a startup script (.profile for sh(1) users or .login for csh(1) users) it is desirable to give information about the type of
       terminal you will usually use on ports which are not hardwired.	These ports are identified in /etc/ttys as dialup or plugboard or arpanet,
       etc.  To specify what terminal type you usually use on these ports, the -m (map) option flag is followed by the appropriate port type iden-
       tifier, an optional baud rate specification, and the terminal type.  (The effect is to ``map'' from some conditions  to	a  terminal  type,
       that  is,  to  tell tset ``If I'm on this kind of port, guess that I'm on that kind of terminal''.)  If more than one mapping is specified,
       the first applicable mapping prevails.  A missing port type identifier matches all identifiers.	Any of the alternate generic  names  given
       in termcap may be used for the identifier.

       A  baudrate  is	specified as with stty(1), and is compared with the speed of the diagnostic output (which should be the control terminal).
       The baud rate test may be any combination of: >, @, <, and !; @ means ``at'' and !  inverts the sense of the test.  To avoid problems  with
       metacharacters,	it  is	best  to place the entire argument to -m within ``''' characters; users of csh(1) must also put a ``'' before any
       ``!'' used here.

       Thus

	      tset -m 'dialup>300:adm3a' -m dialup:dw2 -m 'plugboard:?adm3a'

       causes the terminal type to be set to an adm3a if the port in use is a dialup at a speed greater than 300 baud; to a dw2  if  the  port	is
       (otherwise)  a dialup (i.e. at 300 baud or less).  (NOTE: the examples given here appear to take up more than one line, for text processing
       reasons.  When you type in real tset commands, you must enter them entirely on one line.)  If the type finally determined  by  tset  begins
       with  a	question  mark, the user is asked if s/he really wants that type.  A null response means to use that type; otherwise, another type
       can be entered which will be used instead.  Thus, in the above case, the user will be queried on a plugboard port as to	whether  they  are
       actually using an adm3a.

       If  no  mapping	applies  and a final type option, not preceded by a -m, is given on the command line then that type is used; otherwise the
       type found in the /etc/ttys database will be taken to be the terminal type.  This should always be the case for hardwired ports.

       It is usually desirable to return the terminal type, as finally determined by tset, and information about the terminal's capabilities to  a
       shell's environment.  This can be done using the - option; using the Bourne shell, sh(1):

	      export TERM; TERM=`tset - options...`

       or using the C shell, csh(1):

	      setenv TERM `tset - options...`

       With  csh it is preferable to use the following command in your .login file to initialize the TERM and TERMCAP environment variables at the
       same time.

	      eval `tset -s options...`

       It is also convenient to make an alias in your .cshrc:

	      alias tset 'eval `tset -s !*`'

       This allows the command:

	      tset 2621

       to be invoked at any time to set the terminal and environment.  Note to Bourne Shell users: It is not possible to get this aliasing  effect
       with  a	shell script, because shell scripts cannot set the environment of their parent.  (If a process could set its parent's environment,
       none of this nonsense would be necessary in the first place.)

       These commands cause tset to place the name of your terminal in the variable TERM in the environment; see environ(7).

       Once the terminal type is known, tset engages in terminal driver mode setting.  This normally involves sending an  initialization  sequence
       to  the terminal, setting the single character erase (and optionally the line-kill (full line erase)) characters, and setting special char-
       acter delays.  Tab and newline expansion are turned off during transmission of the terminal initialization sequence.

       On terminals that can backspace but not overstrike (such as a CRT), and when the erase character is the default	erase  character  (`#'	on
       standard systems), the erase character is changed to BACKSPACE (Control-H).

       The options are:

       -ec    set  the	erase  character  to be the named character c on all terminals, the default being the backspace character on the terminal,
	      usually ^H.  The character c can either be typed directly, or entered using the hat notation used here.

       -kc    is similar to -e but for the line kill character rather than the erase character; c defaults to ^X (for purely historical  reasons).
	      The kill characters is left alone if -k is not specified.  The hat notation can also be used for this option.

       -ic    is  similar  to  -e but for the interrupt character rather than the erase character; c defaults to ^C.  The hat notation can also be
	      used for this option.

       -      The name of the terminal finally decided upon is output on the standard output.  This is intended to be captured by  the	shell  and
	      placed in the environment variable TERM.

       -s     Print  the  sequence  of	csh  commands  to  initialize the environment variables TERM and TERMCAP based on the name of the terminal
	      finally decided upon.

       -n     On systems with the Berkeley 4BSD tty driver, specifies that the new tty driver modes should be initialized for this terminal.   For
	      a CRT, the CRTERASE and CRTKILL modes are set only if the baud rate is 1200 or greater.  See tty(4) for more detail.

       -I     suppresses transmitting terminal initialization strings.

       -Q     suppresses printing the ``Erase set to'' and ``Kill set to'' messages.

       If  tset  is  invoked  as reset, it will set cooked and echo modes, turn off cbreak and raw modes, turn on newline translation, and restore
       special characters to a sensible state before any terminal dependent processing is done.  Any special character that is found to be NULL or
       ``-1'' is reset to its default value.  All arguments to tset may be used with reset.

       This  is  most  useful  after  a program dies leaving a terminal in a funny state. You may have to type ``<LF>reset<LF>'' to get it to work
       since <CR> may not work in this state. Often none of this will echo.

EXAMPLES

       These examples all assume the Bourne shell and use the - option.  If you use csh, use one of the variations described above.  Note  that  a
       typical	use  of  tset  in a .profile or .login will also use the -e and -k options, and often the -n or -Q options as well.  These options
       have not been included here to keep the examples small.	(NOTE: some of the examples given here appear to take up more than one	line,  for
       text processing reasons.  When you type in real tset commands, you must enter them entirely on one line.)

       At the moment, you are on a 2621.  This is suitable for typing by hand but not for a .profile, unless you are always on a 2621.

	      export TERM; TERM=`tset - 2621`

       You have an h19 at home which you dial up on, but your office terminal is hardwired and known in /etc/ttys.

	      export TERM; TERM=`tset - -m dialup:h19`

       You have a switch which connects everything to everything, making it nearly impossible to key on what port you are coming in on.  You use a
       vt100 in your office at 9600 baud, and dial up to switch ports at 1200 baud from home on a 2621.  Sometimes you use someone elses  terminal
       at  work,  so  you  want  it to ask you to make sure what terminal type you have at high speeds, but at 1200 baud you are always on a 2621.
       Note the placement of the question mark, and the quotes to protect the greater than and question mark from interpretation by the shell.

	      export TERM; TERM=`tset - -m 'switch>1200:?vt100' -m 'switch<=1200:2621'

       All of the above entries will fall back on the terminal type specified in /etc/ttys if none of the conditions hold.  The following entry is
       appropriate  if	you  always  dial up, always at the same baud rate, on many different kinds of terminals.  Your most common terminal is an
       adm3a.  It always asks you what kind of terminal you are on, defaulting to adm3a.

	      export TERM; TERM=`tset - .PP If the file /etc/ttys is not properly installed and you want to key entirely on  the  baud	rate,  the
	      following can be used:

	      export TERM; TERM=`tset - -m '>1200:vt100' 2621`

       Here  is  a  fancy  example to illustrate the power of tset and to hopelessly confuse anyone who has made it this far.  You dial up at 1200
       baud or less on a concept100, sometimes over switch ports and sometimes over regular dialups.  You use various terminals at  speeds  higher
       than  1200  over switch ports, most often the terminal in your office, which is a vt100.  However, sometimes you log in from the university
       you used to go to, over the ARPANET; in this case you are on an ALTO emulating a dm2500.  You also often log in on various hardwired ports,
       such  as  the console, all of which are properly entered in /etc/ttys.  You want your erase character set to control H, your kill character
       set to control U, and don't want tset to print the ``Erase set to Backspace, Kill set to Control U'' message.

	      export TERM; TERM=`tset -e -k^U -Q - -m 'switch<=1200:concept100' -m 'switch:?vt100' -m dialup:concept100 -m arpanet:dm2500`

FILES

       /etc/ttys port name to terminal type mapping database
       /etc/termcap   terminal capability database

SEE ALSO

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

BUGS

       The tset command is one of the first commands a user must master when getting started on a UNIX system.	Unfortunately, it is  one  of  the
       most  complex, largely because of the extra effort the user must go through to get the environment of the login shell set.  Something needs
       to be done to make all this simpler, either the login(1) program should do this stuff, or a default shell alias should be made, or a way to
       set the environment of the parent should exist.

       This  program can't intuit personal choices for erase, interrupt and line kill characters, so it leaves these set to the local system stan-
       dards.

NOTES

       For compatibility with earlier versions of tset a number of flags are accepted whose use is discouraged:

       -d type	 equivalent to -m dialup:type

       -p type	 equivalent to -m plugboard:type

       -a type	 equivalent to -m arpanet:type

       -	 prints the terminal type on the standard output

       -r	 prints the terminal type on the diagnostic output.

4th Berkeley Distribution					  March 28, 1997							   TSET(1)