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- * @Id: clear.1,v 1.17 2017/08/19 14:12:50 tom Exp @
+ * @Id: clear.1,v 1.23 2020/02/02 23:34:34 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>
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<H1 class="no-header">clear 1</H1>
<PRE>
-<STRONG><A HREF="clear.1.html">clear(1)</A></STRONG>
<STRONG><A HREF="clear.1.html">clear(1)</A></STRONG>
+<STRONG><A HREF="clear.1.html">clear(1)</A></STRONG>
General Commands Manual <STRONG><A HREF="clear.1.html">clear(1)</A></STRONG>
<STRONG>-T</STRONG> <EM>type</EM>
indicates the <EM>type</EM> of terminal. Normally this option is unneces-
sary, because the default is taken from the environment variable
- <STRONG>TERM</STRONG>.
+ <STRONG>TERM</STRONG>. If <STRONG>-T</STRONG> is specified, then the shell variables <STRONG>LINES</STRONG> and <STRONG>COL-</STRONG>
+ <STRONG>UMNS</STRONG> will also be ignored.
<STRONG>-V</STRONG> reports the version of ncurses which was used in this program, and
exits. The options are as follows:
</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
- A <STRONG>clear</STRONG> 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 (<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
+ 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
+ /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 sim-
ilar to the AT&T <STRONG>tput</STRONG>, he added a shell script for the <STRONG>clear</STRONG> command:
- exec tput clear
+ exec tput clear
The remainder of the script in each case is a copyright notice.
- The ncurses <STRONG>clear</STRONG> command began in 1995 by adapting the original BSD
+ The ncurses <STRONG>clear</STRONG> command began in 1995 by adapting the original BSD
<STRONG>clear</STRONG> command (with terminfo, of course).
The <STRONG>E3</STRONG> extension came later:
- <STRONG>o</STRONG> In June 1999, xterm provided an extension to the standard control
- sequence for clearing the screen. Rather than clearing just the
+ <STRONG>o</STRONG> In June 1999, xterm 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'
+ printf '\033[2J'
one could clear the <EM>scrollback</EM> using
- printf '\033[<STRONG>3</STRONG>J'
+ printf '\033[<STRONG>3</STRONG>J'
- This is documented in <EM>XTerm</EM> <EM>Control</EM> <EM>Sequences</EM> as a feature origi-
+ This is documented in <EM>XTerm</EM> <EM>Control</EM> <EM>Sequences</EM> as a feature origi-
nating with xterm.
<STRONG>o</STRONG> A few other terminal developers adopted the feature, e.g., 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. The
- Linux change, part of the 3.0 release, did not mention xterm,
+ <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,
although it was cited in the Red Hat bug report (#683733) which led
to the change.
- <STRONG>o</STRONG> Again, a few other terminal developers adopted the feature. But
+ <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.
- <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
+ <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>.
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 <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
+ 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-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="tput.1.html">tput(1)</A></STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>
- This describes <STRONG>ncurses</STRONG> version 6.0 (patch 20170819).
+ This describes <STRONG>ncurses</STRONG> version 6.2 (patch 20201003).
projects / ncurses.git / blobdiff