.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: tset.1,v 1.31 2016/01/30 15:41:41 tom Exp $
+.\" $Id: tset.1,v 1.43 2016/08/06 23:16:39 tom Exp $
.TH @TSET@ 1 ""
.ie \n(.g .ds `` \(lq
.el .ds `` ``
.ie \n(.g .ds '' \(rq
.el .ds '' ''
+.de bP
+.IP \(bu 4
+..
.SH NAME
-\fB@TSET@\fR, \fBreset\fR \- terminal initialization
+\fB@TSET@\fR, \fB@RESET@\fR \- terminal initialization
.SH SYNOPSIS
\fB@TSET@\fR [\fB\-IQVcqrsw\fR] [\fB\-\fR] [\fB\-e\fR \fIch\fR] [\fB\-i\fR \fIch\fR] [\fB\-k\fR \fIch\fR] [\fB\-m\fR \fImapping\fR] [\fIterminal\fR]
.br
-\fBreset\fR [\fB\-IQVcqrsw\fR] [\fB\-\fR] [\fB\-e\fR \fIch\fR] [\fB\-i\fR \fIch\fR] [\fB\-k\fR \fIch\fR] [\fB\-m\fR \fImapping\fR] [\fIterminal\fR]
+\fB@RESET@\fR [\fB\-IQVcqrsw\fR] [\fB\-\fR] [\fB\-e\fR \fIch\fR] [\fB\-i\fR \fIch\fR] [\fB\-k\fR \fIch\fR] [\fB\-m\fR \fImapping\fR] [\fIterminal\fR]
.SH DESCRIPTION
.SS tset - initialization
-\&\fBTset\fR initializes terminals.
-\fBTset\fR first determines the type of terminal that you are using.
+This program initializes terminals.
+.PP
+First, \fB@TSET@\fR retrieves the current terminal mode settings
+for your terminal.
+It does this by successively testing
+.bP
+the standard error,
+.bP
+standard output,
+.bP
+standard input and
+.bP
+ultimately \*(lq/dev/tty\*(rq
+.PP
+to obtain terminal settings.
+Having retrieved these settings, \fB@TSET@\fP remembers which
+file descriptor to use when updating settings.
+.PP
+Next, \fB@TSET@\fP determines the type of terminal that you are using.
This determination is done as follows, using the first terminal type found.
.PP
1. The \fBterminal\fR argument specified on the command line.
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 \fB\-c\fP or \fB\-w\fP option to select only the window sizing
-versus the other initialization.
-If neither option is given, both are assumed.
.SS reset - reinitialization
.PP
-When invoked as \fBreset\fR, \fB@TSET@\fR sets cooked and echo modes,
+When invoked as \fB@RESET@\fR, \fB@TSET@\fR 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
.sp
- \fB<LF>reset<LF>\fR
+ \fI<LF>\fP\fB@RESET@\fP\fI<LF>\fP
.sp
(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.
.TP
.B \-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.
+not initialized in any way.
+The option \*(``\-\*('' by itself is equivalent but archaic.
.TP
.B \-r
Print the terminal type to the standard error output.
unless \fBsetupterm\fP is not able to detect the window size.
.PP
The arguments for the \fB\-e\fR, \fB\-i\fR, and \fB\-k\fR
-options may either be entered as actual characters or by using the `hat'
+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\*(''.
+.PP
+If neither \fB\-c\fP or \fB\-w\fP is given, both options are assumed.
.
.SH SETTING THE ENVIRONMENT
It is often desirable to enter the terminal type and information about
When \fB@TSET@\fR is used in a startup script it is often desirable to
provide information about the type of terminal used on such ports.
.PP
-The purpose of the \fB\-m\fR option is to map
+The \fB\-m\fR options maps
from some set of conditions to a terminal type, that is, to
tell \fB@TSET@\fR
\*(``If I'm on this port at a particular speed,
and that \fBcsh\fR users insert a backslash character (\*(``\e\*('') before
any exclamation marks (\*(``!\*('').
.SH HISTORY
-The \fB@TSET@\fR command appeared in BSD 3.0. The \fBncurses\fR implementation
+.PP
+A \fBreset\fP command appeared in 2BSD (1979), written by Kurt Shoens.
+.PP
+A separate \fBtset\fP command was provided in 2BSD by Eric Allman.
+While the oldest published source (from 1979) provides both programs,
+Allman's comments in the 2BSD source code indicate
+that he began work in October 1977,
+continuing development over the next few years.
+.PP
+In 1980, Eric Allman modified \fBtset\fP to provide a \*(lqreset\*(rq
+feature when the program was invoked as \fBreset\fP.
+.PP
+The \fBncurses\fR implementation
was lightly adapted from the 4.4BSD sources for a terminfo environment by Eric
S. Raymond <esr@snark.thyrsus.com>.
.SH COMPATIBILITY
-The \fB@TSET@\fR utility has been provided for backward-compatibility with BSD
+.PP
+Neither IEEE Std 1003.1/The Open Group Base Specifications Issue 7
+(POSIX.1-2008) nor
+X/Open Curses Issue 7 documents \fB@TSET@\fP or \fB@RESET@\fP.
+.PP
+The AT&T \fBtput\fP utility (AIX, HPUX, Solaris)
+incorporated the terminal-mode manipulation as well as termcap-based features
+such as resetting tabstops from \fBtset\fP in BSD (4.1c),
+presumably with the intention of making \fBtset\fP obsolete.
+However, each of those systems still provides \fBtset\fP.
+In fact, the commonly-used \fBreset\fP utility
+is always an alias for \fBtset\fP.
+.PP
+The \fB@TSET@\fR utility provides for backward-compatibility with BSD
environments (under most modern UNIXes, \fB/etc/inittab\fR and \fIgetty\fR(1)
can set \fBTERM\fR appropriately for each dial-up line; this obviates what was
\fB@TSET@\fR's most important use). This implementation behaves like 4.4BSD
-tset, with a few exceptions specified here.
+\fBtset\fP, with a few exceptions specified here.
.PP
-The \fB\-S\fR option of BSD tset no longer works;
-it prints an error message to stderr and dies.
+A few options are different
+because the \fBTERMCAP\fR variable
+is no longer supported under terminfo-based \fBncurses\fR:
+.bP
+The \fB\-S\fR option of BSD \fBtset\fP no longer works;
+it prints an error message to the standard error and dies.
+.bP
The \fB\-s\fR option only sets \fBTERM\fR, not \fBTERMCAP\fP.
-Both of these changes are because the \fBTERMCAP\fR variable
-is no longer supported under terminfo-based \fBncurses\fR,
-which makes \fB@TSET@ \-S\fR useless
-(we made it die noisily rather than silently induce lossage).
.PP
-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.
+There was an undocumented 4.4BSD feature
+that invoking \fBtset\fP 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.
.PP
The \fB\-A\fR, \fB\-E\fR, \fB\-h\fR, \fB\-u\fR and \fB\-v\fR
options were deleted from the \fB@TSET@\fR
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 \fB\-m\fR option instead.
-The \fB\-n\fP option remains, but has no effect.
-The \fB\-adnp\fR options are therefore omitted from the usage summary above.
+The \fB\-a\fP, \fB\-d\fP, and \fB\-p\fR options are therefore omitted from the usage summary above.
+.PP
+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 \fB@TSET@\fP provided a
+\fB\-n\fP option to specify that the new terminal driver should be used.
+This implementation does not provide that choice.
.PP
It is still permissible to specify the \fB\-e\fR, \fB\-i\fR,
and \fB\-k\fR options without arguments,
explicitly specify the character.
.PP
As of 4.4BSD,
-executing \fB@TSET@\fR as \fBreset\fR no longer implies the \fB\-Q\fR option.
+executing \fB@TSET@\fR as \fB@RESET@\fR no longer implies the \fB\-Q\fR option.
Also, the interaction between the \- option and the \fIterminal\fR
argument in some historic implementations of \fB@TSET@\fR has been removed.
+.PP
+The \fB\-c\fP and \fB\-w\fP options are not found in earlier implementations.
+However, a different window size-change feature was provided in 4.4BSD.
+.bP
+In 4.4BSD, \fBtset\fP uses the window size from the termcap description
+to set the window size if \fBtset\fP is not able to obtain the window
+size from the operating system.
+.bP
+In ncurses, \fB@TSET@\fR obtains the window size using
+\fBsetupterm\fP, which may be from
+the operating system,
+the \fBLINES\fP and \fBCOLUMNS\fP environment variables or
+the terminal description.
+.PP
+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 \fBsetupterm\fP would still fail).
+For that reason, the \fBLINES\fP and \fBCOLUMNS\fP 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 \fBresize\fP(1) program.
.SH ENVIRONMENT
The \fB@TSET@\fR command uses these environment variables:
.TP 5
.TP 5
TERMCAP
may denote the location of a termcap database.
-If it is not an absolute pathname, e.g., begins with a `/',
+If it is not an absolute pathname, e.g., begins with a \*(``/\*('',
\fB@TSET@\fP removes the variable from the environment before looking
for the terminal description.
.SH FILES
projects / ncurses.git / blobdiff