This program initializes terminals.
First, tset retrieves the current terminal mode settings for your
@@ -79,25 +81,25 @@
1. The terminal argument specified on the command line.
- 2. The value of the TERM environmental variable.
+ 2. The value of the TERM environment variable.
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(1) does this job by setting
- TERM according to the type passed to it by /etc/inittab.)
+ error output device in the /etc/ttys file. (On System V hosts and
+ systems using that convention, getty(8) does this job by setting TERM
+ according to the type passed to it by /etc/inittab.)
4. The default terminal type, "unknown", is not suitable for curses
applications.
If the terminal type was not specified on the command-line, the -m
- option mappings are then applied (see the section TERMINALTYPEMAPPING
- 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 terminal description for the terminal is retrieved. If
- no terminal description is found for the type, the user is prompted for
- another terminal type.
+ option mappings are then applied; see subsection "Terminal Type
+ Mapping". 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
+ terminal description for the terminal is retrieved. If no terminal
+ description is found for the type, the user is prompted for another
+ terminal type.
Once the terminal description is retrieved,
@@ -105,8 +107,8 @@
window size.
If the window size cannot be obtained from the operating system,
- but the terminal description (or environment, e.g., LINES and
- COLUMNS variables specify this), use this to set the operating
+ but the terminal description (or environment, e.g., LINES and
+ COLUMNS variables specify this), use this to set the operating
system's notion of the window size.
o if the "-c" option is enabled, the backspace, interrupt and line
@@ -121,7 +123,7 @@
displayed to the standard error output.
-
When invoked as reset, tset sets the terminal modes to "sane" values:
o sets cooked and echo modes,
@@ -150,75 +152,25 @@
o Also, the terminal will often not echo the command.
-
- The options are as follows:
-
- -c Set control characters and modes.
-
- -ech
- Set the erase character to ch.
-
- -I Do not send the terminal or tab initialization strings to the
- terminal.
-
- -ich
- Set the interrupt character to ch.
-
- -kch
- Set the line kill character to ch.
-
- -mmapping
- Specify a mapping from a port type to a terminal. See the section
- TERMINALTYPEMAPPING for more information.
-
- -Q 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.
-
- -q 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 archaic.
-
- -r Print the terminal type to the standard error output.
-
- -s Print the sequence of shell commands to initialize the environment
- variable TERM to the standard output. See the section SETTINGTHE
- ENVIRONMENT for details.
-
- -V reports the version of ncurses which was used in this program, and
- exits.
-
- -w Resize the window to match the size deduced via setupterm(3x).
- Normally this has no effect, unless setupterm is not able to
- detect the window size.
-
- 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".
-
- If neither -c or -w is given, both options are assumed.
-
-
-
+ 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 option.
- 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
- csh, otherwise, they are for sh(1). Note, the csh 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:
+ 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 environment variable ends in "csh", the commands are for
+ csh(1), otherwise, they are for sh(1). The csh 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 ... `
-
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
+ /etc/ttys file or the TERM environment variable is often something
generic like network, dialup, 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.
@@ -260,141 +212,188 @@
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 csh users insert a backslash character ("\") before any
+ that csh users insert a backslash character ("\") before any
exclamation marks ("!").
-
- A reset command appeared in 1BSD (March 1978), written by Kurt Shoens.
- This program set the erase and kill characters to ^H (backspace) and @
- respectively. Mark Horton improved that in 3BSD (October 1979), adding
- intr, quit, start/stop and eof characters as well as changing the
- program to avoid modifying any user settings. That version of reset
- did not use the termcap database.
+
+ The options are as follows:
+
+ -c Set control characters and modes.
+
+ -ech
+ Set the erase character to ch.
+
+ -I Do not send the terminal or tab initialization strings to the
+ terminal.
+
+ -ich
+ Set the interrupt character to ch.
+
+ -kch
+ Set the line kill character to ch.
+
+ -mmapping
+ Specify a mapping from a port type to a terminal; see subsection
+ "Terminal Type Mapping".
+
+ -Q 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.
+
+ -q 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 archaic.
+
+ -r Print the terminal type to the standard error output.
+
+ -s Print the sequence of shell commands to initialize the environment
+ variable TERM to the standard output; see subsection "Setting the
+ Environment".
+
+ -V reports the version of ncurses which was used in this program, and
+ exits.
+
+ -w Resize the window to match the size deduced via setupterm(3x).
+ Normally this has no effect, unless setupterm is not able to
+ detect the window size.
+
+ 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".
+
+ If neither -c or -w is given, both options are assumed.
+
+
+
+ The tset command uses these environment variables:
- A separate tset command was provided in 1BSD by Eric Allman, using the
- termcap database. Allman's comments in the source code indicate that
- he began work in October 1977, continuing development over the next few
- years.
+ SHELL
+ tells tset whether to initialize TERM using sh(1) or csh(1)
+ syntax.
- According to comments in the source code, the tset program was modified
- in September 1980, to use logic copied from the 3BSD "reset" when it
- was invoked as reset. This version appeared in 4.1cBSD, late in 1982.
+ TERM Denotes your terminal type. Each terminal type is distinct,
+ though many are similar.
- Other developers (e.g., Keith Bostic and Jim Bloom) continued to modify
- tset until 4.4BSD was released in 1993.
+ TERMCAP
+ 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.
- The ncurses implementation was lightly adapted from the 4.4BSD sources
- for a terminfo environment by Eric S. Raymond <esr@snark.thyrsus.com>.
+
+ Neither IEEE Std 1003.1/The Open Group Base Specifications Issue 7
(POSIX.1-2008) nor X/Open Curses Issue 7 documents tset or reset.
- The AT&T tput utility (AIX, HPUX, Solaris) incorporated the terminal-
- mode manipulation as well as termcap-based features such as resetting
- tabstops from tset in BSD (4.1c), presumably with the intention of
- making tset obsolete. However, each of those systems still provides
- tset. In fact, the commonly-used reset utility is always an alias for
+ The AT&T tput utility (AIX, HP-UX, Solaris) incorporated the terminal-
+ mode manipulation as well as termcap-based features such as resetting
+ tabstops from tset in BSD (4.1c), presumably with the intention of
+ making tset obsolete. However, each of those systems still provides
+ tset. In fact, the commonly-used reset utility is always an alias for
tset.
- The tset utility provides for backward-compatibility with BSD
- environments (under most modern UNIXes, /etc/inittab and getty(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.
+ The tset utility provides backward compatibility with BSD environments;
+ under most modern Unices, /etc/inittab and getty(8) can set TERM
+ appropriately for each dial-up line, obviating what was tset's most
+ important use. This implementation behaves like 4.4BSD tset, with a
+ few exceptions we shall consider now.
- A few options are different because the TERMCAP variable is no longer
- supported under terminfo-based ncurses:
+ A few options are different because the TERMCAP variable is no longer
+ supported under terminfo-based ncurses:
- o The -S option of BSD tset no longer works; it prints an error
+ o The -S option of BSD tset no longer works; it prints an error
message to the standard error and dies.
- o The -s option only sets TERM, not TERMCAP.
+ o The -s option only sets TERM, not TERMCAP.
- 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
+ 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.
The -A, -E, -h, -u and -v options were 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, -d, and -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
+ 4.4BSD. None of them were documented in 4.3BSD and all are of limited
+ utility at best. The -a, -d, and -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 -m option instead. The -a, -d, and
-p options are therefore omitted from the usage summary above.
- Very old systems, e.g., 3BSD, used a different terminal driver which
- was replaced in 4BSD in the early 1980s. To accommodate these older
- systems, the 4BSD tset provided a -n option to specify that the new
- terminal driver should be used. This implementation does not provide
+ Very old systems, e.g., 3BSD, used a different terminal driver which
+ was replaced in 4BSD in the early 1980s. To accommodate these older
+ systems, the 4BSD tset provided a -n option to specify that the new
+ terminal driver should be used. This implementation does not provide
that choice.
- It is still permissible to specify the -e, -i, and -k options without
+ It is still permissible to specify the -e, -i, 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 as reset no longer implies the -Q option.
+ As of 4.4BSD, 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.
- The -c and -w options are not found in earlier implementations.
+ The -c and -w options are not found in earlier implementations.
However, a different window size-change feature was provided in 4.4BSD.
- o In 4.4BSD, tset uses the window size from the termcap description
- to set the window size if tset is not able to obtain the window
+ o In 4.4BSD, tset uses the window size from the termcap description
+ to set the window size if tset is not able to obtain the window
size from the operating system.
- o In ncurses, tset obtains the window size using setupterm, which may
- be from the operating system, the LINES and COLUMNS environment
+ o In ncurses, tset obtains the window size using setupterm(3x), which
+ may be from the operating system, the LINES and COLUMNS environment
variables or the terminal description.
- Obtaining the window size from the terminal description is common to
- both implementations, but considered obsolescent. Its only practical
- use is for hardware terminals. Generally speaking, a window size would
- be unset only if there were some problem obtaining the value from the
- operating system (and setupterm would still fail). For that reason,
- the LINES and COLUMNS environment variables may be useful for working
- around window-size problems. Those have the drawback that if the
- window is resized, those variables must be recomputed and reassigned.
- To do this more easily, use the resize(1) program.
-
+ Obtaining the window size from a terminal's type description is common
+ to both implementations, but considered obsolescent. Its only
+ practical use is for hardware terminals. Generally, the window size
+ will remain uninitialized only if there were a problem obtaining the
+ value from the operating system (and setupterm would still fail). The
+ LINES and COLUMNS environment variables may thus be useful for working
+ around window-size problems, but have the drawback that if the window
+ is resized, their values must be recomputed and reassigned. The
+ resize(1) program distributed with xterm(1) assists this activity.
-
- The tset command uses these environment variables:
-
- SHELL
- tells tset whether to initialize TERM using sh(1) or csh(1)
- syntax.
-
- TERM Denotes your terminal type. Each terminal type is distinct,
- though many are similar.
-
- TERMCAP
- 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.
-
-
-
+ A reset command written by Kurt Shoens appeared in 1BSD (March 1978).
+ It set the erase and kill characters to ^H (backspace) and @
+ respectively. Mark Horton improved this reset in 3BSD (October 1979),
+ adding intr, quit, start/stop, and eof characters as well as changing
+ the program to avoid modifying any user settings. That version of
+ reset did not use termcap.
+
+ Eric Allman wrote a distinct tset command for 1BSD, using a forerunner
+ of termcap called ttycap. Allman's comments in the source code
+ indicate that he began work in October 1977, continuing development
+ over the next few years. By late 1979, it had migrated to termcap and
+ handled the TERMCAP variable. Later comments indicate that tset was
+ modified in September 1980 to use logic copied from the 3BSD "reset"
+ program when it was invoked as reset. This version appeared in
+ 4.1cBSD, late in 1982. Other developers such as Keith Bostic and Jim
+ Bloom continued to modify tset until 4.4BSD was released in 1993.
+
+ The ncurses implementation was lightly adapted from the 4.4BSD sources
+ to use the terminfo API by Eric S. Raymond <esr@snark.thyrsus.com>.