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<H1 class="no-header">clear 1 2025-04-05 ncurses 6.6 User commands</H1>
<PRE>
<STRONG><A HREF="clear.1.html">clear(1)</A></STRONG> User commands <STRONG><A HREF="clear.1.html">clear(1)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>clear</STRONG> - clear the terminal screen
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>clear</STRONG> [<STRONG>-x</STRONG>] [<STRONG>-T</STRONG> <EM>terminal-type</EM>]
<STRONG>clear</STRONG> <STRONG>-V</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
<STRONG>clear</STRONG> clears your terminal's screen and its scrollback buffer, if any.
<STRONG>clear</STRONG> retrieves the terminal type from the environment variable <EM>TERM</EM>,
then consults the <EM>terminfo</EM> terminal capability database entry for that
type to determine how to perform these actions.
The capabilities to clear the screen and scrollback buffer are named
"clear" and "E3", respectively. The latter is a <EM>user-defined</EM>
<EM>capability</EM>, applying an extension mechanism introduced in <EM>ncurses</EM> 5.0
(1999).
</PRE><H2><a name="h2-OPTIONS">OPTIONS</a></H2><PRE>
<STRONG>clear</STRONG> recognizes the following options.
<STRONG>-T</STRONG> <EM>type</EM> produces instructions suitable for the terminal <EM>type</EM>.
Normally, this option is unnecessary, because the terminal
type is inferred from the environment variable <EM>TERM</EM>. If this
option is specified, <STRONG>clear</STRONG> ignores the environment variables
<EM>LINES</EM> and <EM>COLUMNS</EM> as well.
<STRONG>-V</STRONG> reports the version of <EM>ncurses</EM> associated with this program
and exits with a successful status.
<STRONG>-x</STRONG> prevents <STRONG>clear</STRONG> from attempting to clear the scrollback buffer.
</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 <STRONG>clear</STRONG>.
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 <STRONG>tput</STRONG> as <STRONG>clear</STRONG>.
</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
A <STRONG>clear</STRONG> command using the <EM>termcap</EM> database and library appeared in 2BSD
(1979). Eighth Edition Unix (1985) later included it.
The commercial Unix arm of AT&T adapted a different BSD program (<STRONG>tset</STRONG>)
to make a new command, <STRONG>tput</STRONG>, and replaced the <STRONG>clear</STRONG> program with a
shell script that called "<STRONG>tput</STRONG> <STRONG>clear</STRONG>".
/usr/bin/tput ${1:+-T$1} clear 2> /dev/null
exit
In 1989, when Keith Bostic revised the BSD <STRONG>tput</STRONG> command to make it
similar to AT&T's <STRONG>tput</STRONG>, he added a <STRONG>clear</STRONG> shell script as well.
exec tput clear
The remainder of the script in each case is a copyright notice.
In 1995, <EM>ncurses</EM>'s <STRONG>clear</STRONG> began by adapting BSD's original <STRONG>clear</STRONG> command
to use <EM>terminfo</EM>. The <STRONG>E3</STRONG> extension came later.
<STRONG>o</STRONG> In June 1999, <EM>xterm</EM> 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 scrollback buffer as well by using
printf '\033[<STRONG>3</STRONG>J'
instead. "XTerm Control Sequences" documents this feature as
originating with <EM>xterm</EM>.
<STRONG>o</STRONG> A few other terminal emulators adopted it, such as PuTTY in 2006.
<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.
Documentation of this change, appearing in Linux 3.0, did not
mention <EM>xterm</EM>, although that program was cited in the Red Hat bug
report (#683733) motivating the feature.
<STRONG>o</STRONG> Subsequently, more terminal developers adopted the feature. The
next relevant step was to change the <EM>ncurses</EM> <STRONG>clear</STRONG> program in 2013
to incorporate this extension.
<STRONG>o</STRONG> In 2013, the <STRONG>E3</STRONG> capability was not exercised by "<STRONG>tput</STRONG> <STRONG>clear</STRONG>". That
oversight 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-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="tput.1.html">tput(1)</A></STRONG>, <STRONG>xterm(1)</STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>
ncurses 6.6 2025-04-05 <STRONG><A HREF="clear.1.html">clear(1)</A></STRONG>
</PRE>
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<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
<li><a href="#h2-OPTIONS">OPTIONS</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-HISTORY">HISTORY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
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