TSET(1) OpenBSD Reference Manual TSET(1)NAME
tset - terminal initialization
SYNOPSIS
tset [-cIQqrSsVw] [-] [-e ch] [-i ch] [-k ch] [-m mapping] [terminal]
reset [-cIQqrSsVw] [-] [-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 environment variable.
3. The terminal type associated with the standard error output
device in the /etc/ttys file.
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 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,
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. 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 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:
- The terminal type is displayed to the standard output, and the
terminal is not initialized in any way. This option has been
deprecated in favor of the -q flag.
-c Set control characters and modes.
-e ch Set the erase character to ch.
-I Do not send the terminal or tab initialization strings to the
terminal.
-i ch Set the interrupt character to ch.
-k ch Set the line kill character to ch.
-m mapping
Specify a mapping from a port type to a terminal. See below for
more information.
-Q Don't 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.
-r Print the terminal type to the standard error output.
-S Print the terminal type and the termcap entry to the standard
output. 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.
-V Report the version of ncurses which was used in this program, and
exit.
-w Resize the window to match the size deduced via setupterm(3).
Normally this has no effect, unless setupterm(3) 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 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(1) and
ksh(1) 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 csh(1),
otherwise, they are for sh(1). Note, the csh(1) 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
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 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(1) users insert a backslash character (`\') before any exclamation
marks (`!').
ENVIRONMENT
The tset command utilizes the SHELL and TERM environment variables.
FILES
/etc/ttys port name to terminal type mapping database
/usr/share/misc/termcap terminal capability database
SEE ALSOcsh(1), sh(1), stty(1), tty(4), termcap(5), ttys(5), environ(7)STANDARDS
The tset command now uses the terminfo(5) database where previous
versions used termcap(5). To make the -s and -S options still work, tset
also reads in the terminal entry from termcap(5). However, this info is
used for setting TERMCAP only. If the terminal type appears in
terminfo(5) but not in termcap(5), the -q option will not set TERMCAP and
the -Q option will not work at all.
The -A, -E, -h, -u, and -v options have been deleted from the tset
utility. 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.
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.
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.
Finally, the tset implementation has been completely redone (as part of
the addition to the system of a IEEE Std 1003.1-1988 (``POSIX'')
compliant terminal interface) and will no longer compile on systems with
older terminal interfaces.
HISTORY
The tset command appeared in 3.0BSD.
OpenBSD 4.9 January 12, 2010 OpenBSD 4.9
