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  System-V-like  UNIXes
       and  systems using that convention, 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  ques-
       tion  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 deter-
       mined, the terminfo entry for the terminal is retrieved.   If  no  ter-
       minfo  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  stan-
       dard  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.  Use the -c or -w
       option to select only the window sizing versus  the  other  initializa-
       tion.  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 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 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 charac-
            ters 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.   Nor-
            mally  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 correctly:

           eval `tset -s options ... `

TERMINAL TYPE MAPPING
       When the terminal is not hardwired into the system (or the current sys-
       tem 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 particu-
       lar 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 opera-
       tor 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 con-
       trol terminal).  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
       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 exclama-
       tion 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
       of these changes are because the TERMCAP variable  is  no  longer  sup-
       ported  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 let-
       ter) 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, -d, and -p options are similarly not docu-
       mented 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 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 argument 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 vari-
            able from the environment before looking for the terminal descrip-
            tion.

FILES
       /etc/ttys
            system port name to terminal type mapping database  (BSD  versions
            only).

       /etc/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 5.9 (patch 20140913).



                                                                       tset(1)
