first determines the type of terminal that
you are using. This determination is done as follows, using the first terminal
- The terminal argument
specified on the command line.
- The value of the
- The terminal type associated with the standard error
output device in the /etc/ttys file.
- The default terminal type, “unknown”.
If the terminal type was not specified on the command line, the
option mappings are then applied (see the
section below for more information). Then, if the terminal type
begins with a question mark (‘
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
“<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.
- Set control characters and modes.
- Set the erase character to
- Do not send the terminal or tab initialization strings to
- Set the interrupt character to
- Set the line kill character to
- Specify a mapping from a port type to a terminal. See the
MAPPING section below for more information.
- 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
- The terminal type is displayed to the standard output, and
the terminal is not initialized in any way.
- Print the terminal type to the standard error output.
- Print the sequence of shell commands to initialize the
TERM to the
standard output. See the
ENVIRONMENT section below for details.
- Report the version of ncurses which was used in this
program, and exit.
- Resize the window to match the size deduced via
this has no effect, unless
setupterm(3) is not able
to detect the window size.
The arguments for the -e
, and -k
may either be entered as actual characters or by using the “hat”
notation, i.e., control-H may be specified as “^H” or
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
ends in “csh”, the commands are for
, otherwise, they are for
. Note, the
commands set and unset the
shell variable “noglob”, leaving it unset. The following line in
files will initialize the environment
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
file or the
environment variable is often
something generic like “network”, “dialup”, or
“unknown”. When tset
is used in a
startup script (.profile
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:
’ 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
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
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
users insert a backslash
’) before any exclamation
command utilizes the
- port name to terminal type mapping database
- terminal capability database
command now uses the
previous versions used
Historic versions of the
entries to 1023 bytes. Modern
entries are often
much larger, making it impossible to store the full entry in the
environment variable. Because of
this, the -S
option is no longer supported (it
prints an error message to the standard error and exits) and the
option only sets
options have been deleted from the
utility. None of them were documented in
and all are of limited utility at best. The
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
option instead. The
option remains, but has no effect. It is still
permissible to specify the -e
without arguments, although it is strongly recommended that such usage be
fixed to explicitly specify the character.
no longer implies the
option. Also, the interaction between the
option and the
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
compliant terminal interface) and will no
longer compile on systems with older terminal interfaces.
utilities first appeared in 1BSD
The original version of tset
was written by
Eric P. Allman
in October 1977, and
was originally written by
. The current version also
contains code by Zeyd M. Ben-Halim
Eric S. Raymond
Thomas E. Dickey