TERM
environmental variable.
/etc/ttys
file.
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.
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 a 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:
TERM
and
TERMCAP
to the standard output.
See the section below on setting the environment for details.
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
''.
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
environmental variable ends in
``csh'',
the commands are for the
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
/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
(
.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 metacharacters, 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 (``!'').
SHELL
and
TERM
environment variables.
/etc/ttys
/usr/share/misc/termcap
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.1'') compliant terminal interface) and will no longer compile on systems with older terminal interfaces.