Provided by: ncurses-bin_6.0+20160625-1ubuntu1_amd64 bug

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 - initialization
       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 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 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.

   reset - reinitialization
       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.

OPTIONS

       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”.

       If neither -c or -w is given, both options are assumed.

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 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  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  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

       Neither IEEE Std 1003.1/The Open Group Base  Specifications  Issue  7  (POSIX.1-2008)  nor
       X/Open Curses Issue 7 documents tset or reset.

       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 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 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 -a, -d, and -p options are therefore omitted
       from the usage summary above.

       Very old systems, e.g., 3BSD, used a different terminal driver which was replaced in  4BSD
       in  the  early  1980s.   To  accommodate  these older systems, the 4BSD tset provided a -n
       option to specify that the new terminal driver should be used.  This  implementation  does
       not provide that choice.

       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.

       The -c and -w options are not found in  earlier  implementations.   However,  a  different
       window size-change feature was provided in 4.4BSD.

       ·   In  4.4BSD,  tset  uses the window size from the termcap description to set the window
           size if tset is not able to obtain the window size from the operating system.

       ·   In ncurses, tset obtains the window size  using  setupterm,  which  may  be  from  the
           operating  system,  the  LINES  and  COLUMNS  environment  variables  or  the terminal
           description.

       Obtaining the window size from the terminal description is common to both implementations,
       but  considered obsolescent.  Its only practical use is for hardware terminals.  Generally
       speaking, a window size would be unset only if there were some problem obtaining the value
       from  the  operating  system (and setupterm would still fail).  For that reason, the LINES
       and COLUMNS environment variables may be useful for working around  window-size  problems.
       Those  have the drawback that if the window is resized, those variables must be recomputed
       and reassigned.  To do this more easily, use the resize(1) program.

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).

       /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 6.0 (patch 20160625).

                                                                                          tset(1)