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Diffstat (limited to 'upstream/debian-unstable/man1/clear.1')
| -rw-r--r-- | upstream/debian-unstable/man1/clear.1 | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/upstream/debian-unstable/man1/clear.1 b/upstream/debian-unstable/man1/clear.1 new file mode 100644 index 00000000..c034b0ea --- /dev/null +++ b/upstream/debian-unstable/man1/clear.1 @@ -0,0 +1,186 @@ +.\"*************************************************************************** +.\" Copyright 2018-2022,2023 Thomas E. Dickey * +.\" Copyright 1998-2016,2017 Free Software Foundation, Inc. * +.\" * +.\" Permission is hereby granted, free of charge, to any person obtaining a * +.\" copy of this software and associated documentation files (the * +.\" "Software"), to deal in the Software without restriction, including * +.\" without limitation the rights to use, copy, modify, merge, publish, * +.\" distribute, distribute with modifications, sublicense, and/or sell * +.\" copies of the Software, and to permit persons to whom the Software is * +.\" furnished to do so, subject to the following conditions: * +.\" * +.\" The above copyright notice and this permission notice shall be included * +.\" in all copies or substantial portions of the Software. * +.\" * +.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * +.\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * +.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * +.\" IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * +.\" DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * +.\" OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * +.\" THE USE OR OTHER DEALINGS IN THE SOFTWARE. * +.\" * +.\" Except as contained in this notice, the name(s) of the above copyright * +.\" holders shall not be used in advertising or otherwise to promote the * +.\" sale, use or other dealings in this Software without prior written * +.\" authorization. * +.\"*************************************************************************** +.\" +.\" $Id: clear.1,v 1.46 2023/12/16 20:32:22 tom Exp $ +.TH clear 1 2023-12-16 "ncurses 6.4" "User commands" +.ie \n(.g \{\ +.ds `` \(lq +.ds '' \(rq +.ds ' \(aq +.\} +.el \{\ +.ie t .ds `` `` +.el .ds `` "" +.ie t .ds '' '' +.el .ds '' "" +.ie t .ds ' \(aq +.el .ds ' ' +.\} +. +.de bP +.ie n .IP \(bu 4 +.el .IP \(bu 2 +.. +. +.SH NAME +\fB\%clear\fP \- +clear the terminal screen +.SH SYNOPSIS +.B clear +.RB [ \-x ] +.RB [ \-T\ \c +.IR terminal-type ] +.PP +.B "clear \-V" +.SH DESCRIPTION +\fB\%clear\fP clears your terminal's screen and its scrollback buffer, +if any. +\fB\%clear\fP retrieves the terminal type from the environment +variable \fITERM\fP, +then consults the \fIterminfo\fP terminal capability database entry for +that type to determine how to perform these actions. +.PP +The capabilities to clear the screen and scrollback buffer are named +\*(``clear\*('' and \*(``E3\*('', respectively. +The latter is a \fIuser-defined capability\fP, +applying an extension mechanism introduced in \fI\%ncurses\fP 5.0 +(1999). +.SH OPTIONS +\fB\%clear\fP recognizes the following options. +.TP 9 \" "-T type" + 2n +.B \-T \fItype\fP +produces instructions suitable for the terminal \fItype\fP. +Normally, +this option is unnecessary, +because the terminal type is inferred from the environment variable +\fITERM\fP. +If this option is specified, +\fB\%clear\fP ignores the environment variables \fILINES\fP and +\fI\%COLUMNS\fP as well. +.TP +.B \-V +reports the version of \fI\%ncurses\fP associated with this program and +exits with a successful status. +.TP +.B \-x +prevents \fB\%clear\fP from attempting to clear the scrollback buffer. +.SH PORTABILITY +Neither IEEE Std 1003.1/The Open Group Base Specifications Issue 7 +(POSIX.1-2008) nor X/Open Curses Issue 7 documents \fB\%clear\fP. +.PP +The latter documents \fBtput\fP, +which could be used to replace this utility either via a shell script or +by an alias +(such as a symbolic link) +to run \fB\%tput\fP as \fB\%clear\fP. +.SH HISTORY +A \fBclear\fP command using the \fItermcap\fP database and library +appeared in 2BSD (1979). +.\" https://minnie.tuhs.org/cgi-bin/utree.pl?file=2BSD/src/clear.c +Eighth Edition Unix (1985) later included it. +.PP +The commercial Unix arm of AT&T adapted a different BSD program +(\fBtset\fP) to make a new command, +\fBtput\fP, +and replaced the \fBclear\fP program with a shell script that called +\*(``\fBtput clear\fP\*(''. +.PP +.RS 4 +.EX +/usr/bin/tput ${1:+\-T$1} clear 2> /dev/null +exit +.EE +.RE +.PP +In 1989, when Keith Bostic revised the BSD \fBtput\fP command +to make it similar to AT&T's \fBtput\fP, +he added a \fBclear\fP shell script as well. +.\" https://minnie.tuhs.org/cgi-bin/utree.pl?file=Net2/usr/src/usr.bin/\ +.\" tput/clear.sh +.PP +.RS 4 +.EX +exec tput clear +.EE +.RE +.PP +The remainder of the script in each case is a copyright notice. +.PP +In 1995, +\fI\%ncurses\fP's \fBclear\fP began by adapting BSD's original +\fBclear\fP command to use \fIterminfo\fP. +The \fBE3\fP extension came later. +.bP +In June 1999, \fIxterm\fP provided an extension to the standard control +sequence for clearing the screen. +Rather than clearing just the visible part of the screen using +.RS 8 +.PP +.EX +printf \*'\e033[2J\*' +.EE +.RE +.IP +one could clear the scrollback buffer as well by using +.RS 8 +.PP +.EX +printf \*'\e033[\fB3\fPJ\*' +.EE +.RE +.IP +instead. +\*(``XTerm Control Sequences\fP\*('' documents this feature as +originating with \fIxterm\fP. +.bP +A few other terminal emulators adopted it, +such as PuTTY in 2006. +.bP +In April 2011, a Red Hat developer submitted a patch to the Linux +kernel, modifying its console driver to do the same thing. +Documentation of this change, +appearing in Linux 3.0, +did not mention \fIxterm\fP, +although that program was cited in the Red Hat bug report (#683733) +motivating the feature. +.bP +Subsequently, +more terminal developers adopted the feature. +The next relevant step was to change the \fI\%ncurses\fP \fBclear\fP +program in 2013 to incorporate this extension. +.bP +In 2013, +the \fBE3\fP capability was not exercised by +\*(``\fB\%tput clear\fP\*(''. +That oversight was addressed in 2016 by reorganizing \fB\%tput\fP to +share its logic with \fB\%clear\fP and \fB\%tset\fP. +.SH SEE ALSO +\fB\%tput\fP(1), +\fB\%xterm\fP(1), +\fB\%terminfo\fP(5) |