tset - terminal initialization
tset [-IQqrSsV] [-] [-e ch] [-i ch] [-k ch] [-m mapping]
reset [-IQqrSsV] [-] [-e ch] [-i ch] [-k ch] [-m mapping]
tset initializes terminals. tset first determines the type
that you are using. This determination is done as follows,
first terminal type found:
1. The terminal argument specified on the command
2. The value of the TERM environment variable.
3. The terminal type associated with the standard
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
confirmation of the terminal type. An empty response confirms the type,
or another type can be entered to specify a new type. Once
type has been determined, the termcap entry for the terminal
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,
and line kill characters (among many other things) are
set and the
terminal and tab initialization strings are sent to the
output. Finally, if the erase, interrupt and line kill
changed, or are not set to their default values, their values are displayed
to the standard error output.
When invoked as reset, tset sets cooked and echo modes,
turns off cbreak
and raw modes, turns on newline translation and resets any
characters to their default values before doing the terminal
described above. This is useful after a program dies
leaving a terminal
in an abnormal state. Note, you may have to type
(the line-feed character is normally control-J) to get the
work, as carriage-return may no longer work in the abnormal
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
deprecated in favor of the -q flag.
-e ch Set the erase character to ch.
-I Do not send the terminal or tab initialization
strings to the
-i ch Set the interrupt character to ch.
-k ch Set the line kill character to ch.
Specify a mapping from a port type to a terminal.
See below for
-Q Don't display any values for the erase, interrupt
and line kill
-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
output. See the section below on setting the environment for details.
-s Print the sequence of shell commands to initialize
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
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 [Toc] [Back]
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
are written to the standard output, separated by a space and
terminating newline. This can be assigned to an array by
ksh(1) users and then used like any other shell array.
When the -s option is specified, the commands to enter the
into the shell's environment are written to the standard
output. If the
SHELL environment variable ends in ``csh'', the commands are
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
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 term=(`tset -S options ...`)
setenv TERM $term
setenv TERMCAP "$term"
TERMINAL TYPE MAPPING [Toc] [Back]
When the terminal is not hardwired into the system (or the
information is incorrect), the terminal type derived from
file or the TERM environment variable is often something
``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
The purpose of the -m option is to ``map'' from some set of
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
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
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
If no port type is specified, the terminal type will match
any port type,
for example, ``-m dialup:vt100 -m :?xterm'' will cause any
regardless of baud rate, to match the terminal type
``vt100'', and any
non-dialup port type to match the terminal type ``?xterm''.
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
-m option argument be placed within single quote characters,
csh(1) users insert a backslash character (`') before any
The tset command utilizes the SHELL and TERM environment
/etc/ttys port name to terminal type mapping
/usr/share/misc/termcap terminal capability database
csh(1), sh(1), stty(1), tty(4), termcap(5), ttys(5), environ(7)
The tset command now uses the terminfo(5) database where
used termcap(5). To make the -s and -S options still
also reads in the terminal entry from termcap(5). However,
this info is
used for setting TERMCAP only. If the terminal type appears
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
at best. The -a, -d and -p options are similarly not
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
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
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
terminal interface) and will no longer compile on systems with older
The tset command appeared in 3.0BSD.
OpenBSD 3.6 November 15, 1998
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