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- * Copyright 2018,2020 Thomas E. Dickey *
+ * Copyright 2018-2020,2021 Thomas E. Dickey *
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* *
* Permission is hereby granted, free of charge, to any person obtaining a *
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- * @Id: clear.1,v 1.23 2020/02/02 23:34:34 tom Exp @
+ * @Id: clear.1,v 1.26 2021/12/26 00:13:25 tom Exp @
* these would be fallbacks for DS/DE,
* but groff changed the meaning of the macros.
-->
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-<TITLE>@CLEAR@ 1</TITLE>
+<TITLE>clear 1</TITLE>
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-<H1 class="no-header">@CLEAR@ 1</H1>
+<H1 class="no-header">clear 1</H1>
<PRE>
-<B><A HREF="clear.1.html">clear(1)</A></B> General Commands Manual <B><A HREF="clear.1.html">clear(1)</A></B>
+<STRONG><A HREF="clear.1.html">clear(1)</A></STRONG> General Commands Manual <STRONG><A HREF="clear.1.html">clear(1)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
- <B>clear</B> - clear the terminal screen
+ <STRONG>clear</STRONG> - clear the terminal screen
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
- <B>clear</B> [<B>-T</B><I>type</I>] [<B>-V</B>] [<B>-x</B>]
+ <STRONG>clear</STRONG> [<STRONG>-T</STRONG><EM>type</EM>] [<STRONG>-V</STRONG>] [<STRONG>-x</STRONG>]
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
- <B>clear</B> clears your screen if this is possible, including its scrollback
- buffer (if the extended "E3" capability is defined). <B>clear</B> looks in
- the environment for the terminal type given by the environment variable
- <B>TERM</B>, and then in the <B>terminfo</B> database to determine how to clear the
- screen.
-
- <B>clear</B> writes to the standard output. You can redirect the standard
- output to a file (which prevents <B>clear</B> from actually clearing the
- screen), and later <B>cat</B> the file to the screen, clearing it at that
+ <STRONG>clear</STRONG> clears your terminal's screen if this is possible, including the
+ terminal's scrollback buffer (if the extended "E3" capability is
+ defined). <STRONG>clear</STRONG> looks in the environment for the terminal type given
+ by the environment variable <STRONG>TERM</STRONG>, and then in the <STRONG>terminfo</STRONG> database to
+ determine how to clear the screen.
+
+ <STRONG>clear</STRONG> writes to the standard output. You can redirect the standard
+ output to a file (which prevents <STRONG>clear</STRONG> from actually clearing the
+ screen), and later <STRONG>cat</STRONG> the file to the screen, clearing it at that
point.
</PRE><H2><a name="h2-OPTIONS">OPTIONS</a></H2><PRE>
- <B>-T</B> <I>type</I>
- indicates the <I>type</I> of terminal. Normally this option is
+ <STRONG>-T</STRONG> <EM>type</EM>
+ indicates the <EM>type</EM> of terminal. Normally this option is
unnecessary, because the default is taken from the environment
- variable <B>TERM</B>. If <B>-T</B> is specified, then the shell variables <B>LINES</B>
- and <B>COLUMNS</B> will also be ignored.
+ variable <STRONG>TERM</STRONG>. If <STRONG>-T</STRONG> is specified, then the shell variables <STRONG>LINES</STRONG>
+ and <STRONG>COLUMNS</STRONG> will also be ignored.
- <B>-V</B> reports the version of ncurses which was used in this program, and
+ <STRONG>-V</STRONG> reports the version of ncurses which was used in this program, and
exits. The options are as follows:
- <B>-x</B> do not attempt to clear the terminal's scrollback buffer using the
+ <STRONG>-x</STRONG> do not attempt to clear the terminal's scrollback buffer using the
extended "E3" capability.
</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
- A <B>clear</B> command appeared in 2.79BSD dated February 24, 1979. Later
+ A <STRONG>clear</STRONG> command appeared in 2.79BSD dated February 24, 1979. Later
that was provided in Unix 8th edition (1985).
- AT&T adapted a different BSD program (<B>tset</B>) to make a new command
- (<B>tput</B>), and used this to replace the <B>clear</B> command with a shell script
- which calls <B>tput</B> <B>clear</B>, e.g.,
+ AT&T adapted a different BSD program (<STRONG>tset</STRONG>) to make a new command
+ (<STRONG>tput</STRONG>), and used this to replace the <STRONG>clear</STRONG> command with a shell script
+ which calls <STRONG>tput</STRONG> <STRONG>clear</STRONG>, e.g.,
/usr/bin/tput ${1:+-T$1} clear 2> /dev/null
exit
- In 1989, when Keith Bostic revised the BSD <B>tput</B> command to make it
- similar to the AT&T <B>tput</B>, he added a shell script for the <B>clear</B>
+ In 1989, when Keith Bostic revised the BSD <STRONG>tput</STRONG> command to make it
+ similar to the AT&T <STRONG>tput</STRONG>, he added a shell script for the <STRONG>clear</STRONG>
command:
exec tput clear
The remainder of the script in each case is a copyright notice.
- The ncurses <B>clear</B> command began in 1995 by adapting the original BSD
- <B>clear</B> command (with terminfo, of course).
+ The ncurses <STRONG>clear</STRONG> command began in 1995 by adapting the original BSD
+ <STRONG>clear</STRONG> command (with terminfo, of course).
- The <B>E3</B> extension came later:
+ The <STRONG>E3</STRONG> extension came later:
- <B>o</B> In June 1999, xterm provided an extension to the standard control
+ <STRONG>o</STRONG> In June 1999, <STRONG>xterm</STRONG> provided an extension to the standard control
sequence for clearing the screen. Rather than clearing just the
visible part of the screen using
printf '\033[2J'
- one could clear the <I>scrollback</I> using
+ one could clear the <EM>scrollback</EM> using
- printf '\033[<B>3</B>J'
+ printf '\033[<STRONG>3</STRONG>J'
- This is documented in <I>XTerm</I> <I>Control</I> <I>Sequences</I> as a feature
- originating with xterm.
+ This is documented in <EM>XTerm</EM> <EM>Control</EM> <EM>Sequences</EM> as a feature
+ originating with <STRONG>xterm</STRONG>.
- <B>o</B> A few other terminal developers adopted the feature, e.g., PuTTY in
+ <STRONG>o</STRONG> A few other terminal developers adopted the feature, e.g., PuTTY in
2006.
- <B>o</B> In April 2011, a Red Hat developer submitted a patch to the Linux
+ <STRONG>o</STRONG> 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,
+ Linux change, part of the 3.0 release, did not mention <STRONG>xterm</STRONG>,
although it was cited in the Red Hat bug report (#683733) which led
to the change.
- <B>o</B> Again, a few other terminal developers adopted the feature. But
- the next relevant step was a change to the <B>clear</B> program in 2013 to
+ <STRONG>o</STRONG> Again, a few other terminal developers adopted the feature. But
+ the next relevant step was a change to the <STRONG>clear</STRONG> program in 2013 to
incorporate this extension.
- <B>o</B> In 2013, the <B>E3</B> extension was overlooked in <B>tput</B> with the "clear"
- parameter. That was addressed in 2016 by reorganizing <B>tput</B> to
- share its logic with <B>clear</B> and <B>tset</B>.
+ <STRONG>o</STRONG> In 2013, the <STRONG>E3</STRONG> extension was overlooked in <STRONG>tput</STRONG> with the "clear"
+ parameter. That was addressed in 2016 by reorganizing <STRONG>tput</STRONG> to
+ share its logic with <STRONG>clear</STRONG> and <STRONG>tset</STRONG>.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
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 latter documents <B>tput</B>, which could be used to replace this utility
+ The latter documents <STRONG>tput</STRONG>, which could be used to replace this utility
either via a shell script or by an alias (such as a symbolic link) to
- run <B>tput</B> as <B>clear</B>.
+ run <STRONG>tput</STRONG> as <STRONG>clear</STRONG>.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
- <B><A HREF="tput.1.html">tput(1)</A></B>, <B><A HREF="terminfo.5.html">terminfo(5)</A></B>
+ <STRONG><A HREF="tput.1.html">tput(1)</A></STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>, <STRONG>xterm(1)</STRONG>.
- This describes <B>ncurses</B> version 6.2 (patch 20210612).
+ This describes <STRONG>ncurses</STRONG> version 6.3 (patch 20220115).
- <B><A HREF="clear.1.html">clear(1)</A></B>
+ <STRONG><A HREF="clear.1.html">clear(1)</A></STRONG>
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