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tset(1)                                                                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 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 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  out-
       put.   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 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 trans-
       lation 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 informa-
            tion.

       -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, other-
       wise, 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 system information is incorrect) the termi-
       nal 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 informa-
       tion 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 output
       (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 cur-
       rent 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-charac-
       ters, 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 <esrATsnark.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 ter-
       minfo-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 limited utility 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.  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 recom-
       mended 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 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 20090207).



                                                                       tset(1)