ncurses 6.3 - patch 20220129

[ncurses.git] / man / clear.1

diff --git a/man/clear.1 b/man/clear.1
index feb46859b197e674d210dfb10d8585e07f9bdb92..a854baae0d393f5e7c1b600cbc6403ffbadfa373 100644 (file)
--- a/man/clear.1
+++ b/man/clear.1
@@ -1,5 +1,6 @@
 .\"***************************************************************************
-.\" Copyright (c) 1998-2013,2016 Free Software Foundation, Inc.              *
+.\" Copyright 2018-2020,2021 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            *
@@ -26,41 +27,69 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
-.\" $Id: clear.1,v 1.14 2016/11/19 21:30:46 tom Exp $
+.\" $Id: clear.1,v 1.26 2021/12/26 00:13:25 tom Exp $
 .TH @CLEAR@ 1 ""
 .\" these would be fallbacks for DS/DE,
 .\" but groff changed the meaning of the macros.
 .de NS
-.sp .5
-.in +4
+.ie n  .sp
+.el    .sp .5
+.ie n  .in +4
+.el    .in +2
 .nf
 .ft C                  \" Courier
 ..
 .de NE
 .fi
 .ft R
-.in -4
+.ie n  .in -4
+.el    .in -2
 ..
 .ie \n(.g .ds `` \(lq
 .el       .ds `` ``
 .ie \n(.g .ds '' \(rq
 .el       .ds '' ''
 .de bP
-.IP \(bu 4
+.ie n  .IP \(bu 4
+.el    .IP \(bu 2
 ..
 .ds n 5
 .SH NAME
-\fB@CLEAR@\fR \- clear the terminal screen
+\fB@CLEAR@\fP \- clear the terminal screen
 .SH SYNOPSIS
-\fB@CLEAR@\fR
+\fB@CLEAR@\fP [\fB\-T\fP\fItype\fP] [\fB\-V\fP] [\fB\-x\fP]
 .br
 .SH DESCRIPTION
-\fB@CLEAR@\fR clears your screen if this is possible,
-including its scrollback buffer (if the extended \*(``E3\*('' capability is defined).
-\fB@CLEAR@\fR looks in the environment for the terminal type and then in the
-\fBterminfo\fR database to determine how to clear the screen.
+\fB@CLEAR@\fP clears your terminal's screen if this is possible,
+including the terminal's scrollback buffer
+(if the extended \*(``E3\*('' capability is defined).
+\fB@CLEAR@\fP looks in the environment for the terminal type
+given by the environment variable \fBTERM\fP,
+and then in the
+\fBterminfo\fP database to determine how to clear the screen.
 .PP
-\fB@CLEAR@\fR ignores any command-line parameters that may be present.
+\fB@CLEAR@\fP writes to the standard output.
+You can redirect the standard output to a file (which prevents
+\fB@CLEAR@\fP from actually clearing the screen),
+and later \fBcat\fP the file to the screen, clearing it at that point.
+.SH OPTIONS
+.PP
+.TP 5
+.B \-T \fItype\fP
+indicates the \fItype\fP of terminal.
+Normally this option is
+unnecessary, because the default is taken from the environment
+variable \fBTERM\fP.
+If \fB\-T\fP is specified, then the shell
+variables \fBLINES\fP and \fBCOLUMNS\fP will also be ignored.
+.TP
+.B \-V
+reports the version of ncurses which was used in this program, and exits.
+The options are as follows:
+.TP
+.B \-x
+do not attempt to clear the terminal's scrollback buffer
+using the extended \*(``E3\*('' capability.
 .SH HISTORY
 A \fBclear\fP command appeared in 2.79BSD dated February 24, 1979.
 Later that was provided in Unix 8th edition (1985).
@@ -88,7 +117,7 @@ BSD \fBclear\fP command (with terminfo, of course).
 .PP
 The \fBE3\fP extension came later:
 .bP
-In June 1999, xterm provided an extension to the standard control
+In June 1999, \fBxterm\fP provided an extension to the standard control
 sequence for clearing the screen.
 Rather than clearing just the visible part of the screen using
 .NS
@@ -101,17 +130,18 @@ printf '\\033[\fB3\fPJ'
 .NE
 .IP
 This is documented in \fIXTerm Control Sequences\fP as a feature originating
-with xterm.
+with \fBxterm\fP.
 .bP
 A few other terminal developers adopted the feature, e.g., 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.
-The Linux change, part of the 3.0 release, did not mention xterm,
+The Linux change, part of the 3.0 release, did not mention \fBxterm\fP,
 although it was cited in the Red Hat bug report (#683733)
 which led to the change.
 .bP
-Again, a few other terminal developers adopted the feature.  But the
+Again, a few other terminal developers adopted the feature.
+But the
 next relevant step was a change to the \fBclear\fP program in 2013
 to incorporate this extension.
 .bP
@@ -127,7 +157,7 @@ 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 SEE ALSO
-\fB@TPUT@\fR(1), \fBterminfo\fR(\*n)
+\fB@TPUT@\fP(1), \fBterminfo\fP(\*n), \fBxterm\fP(1).
 .PP
-This describes \fBncurses\fR
+This describes \fBncurses\fP
 version @NCURSES_MAJOR@.@NCURSES_MINOR@ (patch @NCURSES_PATCH@).