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.\"	@(#)tset.1	8.1 (Berkeley) 6/9/93
.\"
.Dd $Mdocdate: October 13 2022 $
.Dt TSET 1
.Os
.Sh NAME
.Nm tset ,
.Nm reset
.Nd terminal initialization
.Sh SYNOPSIS
.Nm tset
.Op Fl cIQqrsVw
.Op Fl
.Op Fl e Ar ch
.Op Fl i Ar ch
.Op Fl k Ar ch
.Op Fl m Ar mapping
.Op Ar terminal
.Nm reset
.Op Fl cIQqrsVw
.Op Fl
.Op Fl e Ar ch
.Op Fl i Ar ch
.Op Fl k Ar ch
.Op Fl m Ar mapping
.Op Ar terminal
.Sh DESCRIPTION
.Nm tset
initializes terminals.
.Nm tset
first determines the type of terminal that you are using.
This determination is done as follows, using the first terminal type found:
.Bl -enum -offset indent
.It
The
.Ar terminal
argument specified on the command line.
.It
The value of the
.Ev TERM
environment variable.
.It
The terminal type associated with the standard error output device in the
.Pa /etc/ttys
file.
.It
The default terminal type,
.Dq unknown .
.El
.Pp
If the terminal type was not specified on the command line, the
.Fl m
option mappings are then applied (see the
.Sx TERMINAL TYPE MAPPING
section below for more information).
Then, if the terminal type begins with a question mark
.Pq Ql \&? ,
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.
.Pp
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
.Fl c
or
.Fl w
option to select only the window sizing versus the other initialization.
If neither option is given, both are assumed.
.Pp
When invoked as
.Nm reset ,
.Nm 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
.Dq <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.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl
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
.Fl q
flag.
.It Fl c
Set control characters and modes.
.It Fl e Ar ch
Set the erase character to
.Ar ch .
.It Fl I
Do not send the terminal or tab initialization strings to the terminal.
.It Fl i Ar ch
Set the interrupt character to
.Ar ch .
.It Fl k Ar ch
Set the line kill character to
.Ar ch .
.It Fl m Ar mapping
Specify a mapping from a port type to a terminal.
See the
.Sx TERMINAL TYPE MAPPING
section below for more information.
.It Fl Q
Don't display any values for the erase, interrupt and line kill characters.
Normally
.Nm
displays the values for control characters which differ from the system's
default values.
.It Fl q
The terminal type is displayed to the standard output, and the terminal is
not initialized in any way.
.It Fl r
Print the terminal type to the standard error output.
.It Fl s
Print the sequence of shell commands to initialize the environment variable
.Ev TERM
to the standard output.
See the
.Sx SETTING THE ENVIRONMENT
section below for details.
.It Fl V
Report the version of ncurses which was used in this program, and exit.
.It Fl w
Resize the window to match the size deduced via
.Xr setupterm 3 .
Normally this has no effect, unless
.Xr setupterm 3
is not able to detect the window size.
.El
.Pp
The arguments for the
.Fl e ,
.Fl i ,
and
.Fl k
options may either be entered as actual characters or by using the
.Dq hat
notation, i.e., control-H may be specified as
.Dq ^H
or
.Dq ^h .
.Sh 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
.Fl s
option.
.Pp
When the
.Fl s
option is specified, the commands to enter the information into the
shell's environment are written to the standard output.
If the
.Ev SHELL
environment variable ends in
.Dq csh ,
the commands are for
.Xr csh 1 ,
otherwise, they are for
.Xr sh 1 .
Note, the
.Xr csh 1
commands set and unset the shell variable
.Dq noglob ,
leaving it unset.
The following line in the
.Pa .login
or
.Pa .profile
files will initialize the environment correctly:
.Bd -literal -offset indent
eval \`tset -s options ... \`
.Ed
.Sh 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
.Pa /etc/ttys
file or the
.Ev TERM
environment variable is often something generic like
.Dq network ,
.Dq dialup ,
or
.Dq unknown .
When
.Nm tset
is used in a startup script
.Pf ( Pa .profile
for
.Xr sh 1
users or
.Pa .login
for
.Xr csh 1
users), it is often desirable to provide information about the type of
terminal used on such ports.
.Pp
The purpose of the
.Fl m
option is to
.Dq map
from some set of conditions to a terminal type, that is, to
tell
.Nm tset :
.Do
If I'm on this port at a particular speed, guess that I'm on that
kind of terminal
.Dc .
.Pp
The argument to the
.Fl m
option consists of an optional port type, an optional operator, an optional
baud rate specification, an optional colon
.Pq Ql \&:
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:
.Ql > ,
.Ql < ,
.Ql @ ,
and
.Ql \&! ;
.Ql >
means greater than,
.Ql <
means less than,
.Ql @
means equal to,
and
.Ql \&!
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 controlling terminal).
The terminal type is a string.
.Pp
If the terminal type is not specified on the command line, the
.Fl 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.
.Pp
For example, consider the following mapping:
.Dq dialup>9600:vt100 .
The port type is
.Dq dialup ,
the operator is
.Dq > ,
the baud rate specification is
.Dq 9600 ,
and the terminal type is
.Dq vt100 .
The result of this mapping is to specify that if the terminal type is
.Dq dialup ,
and the baud rate is greater than 9600 baud, a terminal type of
.Dq vt100
will be used.
.Pp
If no port type is specified, the terminal type will match any port type,
for example,
.Dq -m dialup:vt100 -m :?xterm
will cause any dialup port, regardless of baud rate, to match the terminal
type
.Dq vt100 ,
and any non-dialup port type to match the terminal type
.Dq ?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
.Ar xterm
terminal.
.Pp
No whitespace characters are permitted in the
.Fl m
option argument.
Also, to avoid problems with meta-characters, it is suggested that the entire
.Fl m
option argument be placed within single quote characters, and that
.Xr csh 1
users insert a backslash character
.Pq Ql \e
before any exclamation marks
.Pq Ql \&! .
.Sh ENVIRONMENT
The
.Nm tset
command utilizes the
.Ev SHELL
and
.Ev TERM
environment variables.
.Sh FILES
.Bl -tag -width /usr/share/terminfo -compact
.It Pa /etc/ttys
port name to terminal type mapping database
.It Pa /usr/share/terminfo
terminal capability database
.El
.Sh SEE ALSO
.Xr csh 1 ,
.Xr sh 1 ,
.Xr stty 1 ,
.Xr tty 4 ,
.Xr terminfo 5 ,
.Xr ttys 5 ,
.Xr environ 7
.Sh STANDARDS
The
.Nm tset
command now uses the
.Xr terminfo 5
database where previous versions used
.Xr termcap 5 .
.Pp
Historic versions of the
.Xr termcap 3
library limited entries to 1023 bytes.
Modern
.Xr terminfo 3
entries are often much larger, making it impossible to
store the full entry in the
.Ev TERMCAP
environment variable.
Because of this, the
.Fl S
option is no longer supported (it prints an error message to the standard
error and exits) and the
.Fl s
option only sets
.Ev TERM ,
not
.Ev TERMCAP .
.Pp
The
.Fl A ,
.Fl E ,
.Fl h ,
.Fl u ,
and
.Fl v
options have been deleted from the
.Nm tset
utility.
None of them were documented in
.Bx 4.3
and all are of limited utility at best.
The
.Fl a ,
.Fl d
and
.Fl 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
.Fl m
option instead.
The
.Fl n
option remains, but has no effect.
It is still permissible to specify the
.Fl e ,
.Fl i
and
.Fl k
options without arguments, although it is strongly recommended that such
usage be fixed to explicitly specify the character.
.Pp
Executing
.Nm tset
as
.Nm reset
no longer implies the
.Fl Q
option.
Also, the interaction between the
.Fl
option and the
.Ar terminal
argument in some historic implementations of
.Nm tset
has been removed.
.Pp
Finally, the
.Nm tset
implementation has been completely redone (as part of the addition to the
system of a
.St -p1003.1-88
compliant terminal interface) and will no longer compile on systems with
older terminal interfaces.
.Sh HISTORY
The
.Nm tset
and
.Nm reset
utilities first appeared in
.Bx 1 .
.Sh AUTHORS
.An -nosplit
The original version of
.Nm tset
was written by
.An Eric P. Allman
in October 1977, and
.Nm reset
was originally written by
.An Kurt Shoens .
The current version also contains code by
.An Zeyd M. Ben-Halim ,
.An Eric S. Raymond ,
and
.An Thomas E. Dickey .