- terminal initialization
] [-e ch
] [ -k ch
] [-m mapping
] [-e ch
] [ -k ch
] [-m mapping
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
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
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
mappings are then applied (see the section TERMINAL TYPE MAPPING
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.
Use the -c
option to select only the window sizing versus
the other initialization. If neither option is given, both are assumed.
When invoked as reset
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
(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:
- Set control characters and modes.
- Set the erase character to ch.
- Do not send the terminal or tab initialization strings to the
- Set the interrupt character to ch.
- Set the line kill character to ch.
- Specify a mapping from a port type to a terminal. See the section
TERMINAL TYPE MAPPING for more information.
- 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.
- 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
- Print the terminal type to the standard error output.
- Print the sequence of shell commands to initialize the environment
variable TERM to the standard output. See the section SETTING
THE ENVIRONMENT for details.
- reports the version of ncurses which was used in this program, and
- Resize the window to match the size deduced via setupterm. Normally
this has no effect, unless setupterm is not able to detect the
The arguments for the -e
, 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''.
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
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
environmental variable ends in ``csh'', the commands are for
, otherwise, they are for sh
. Note, the csh
set and unset the shell variable noglob
, leaving it unset. The
following line in the .login
files will initialize
the environment correctly:
eval `tset -s options ... `
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
, 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
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
option argument be placed within single quote characters, and that
users insert a backslash character (``\'') before any exclamation
command appeared in BSD 3.0. The ncurses
was lightly adapted from the 4.4BSD sources for a terminfo environment by Eric
S. Raymond <firstname.lastname@example.org>.
utility has been provided for backward-compatibility with BSD
environments (under most modern UNIXes, /etc/inittab
(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.
option of BSD tset no longer works; it prints an error message to
stderr and dies. The -s
option only sets TERM
. Both these changes are because the TERMCAP
no longer supported under terminfo-based ncurses
, which makes tset
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.
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
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
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
, 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
no longer implies the
option. Also, the interaction between the - option and the
argument in some historic implementations of tset
command uses these environment variables:
- tells tset whether to initialize TERM using sh or
- Denotes your terminal type. Each terminal type is distinct, though many
- 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.
- system port name to terminal type mapping database (BSD versions
- terminal capability database
csh(1), sh(1), stty(1), curs_terminfo(3X), tty(4), terminfo(5), ttys(5),
This describes ncurses
version 5.9 (patch 20130511).