+ <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>
+ <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 <STRONG>TERM</STRONG>. If <STRONG>-T</STRONG> is specified, then the shell variables <STRONG>LINES</STRONG>
+ and <STRONG>COLUMNS</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:
+
+ <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 <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
+ 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 <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 <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, <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 <EM>scrollback</EM> using
+
+ printf '\033[<STRONG>3</STRONG>J'
+
+ This is documented in <EM>XTerm</EM> <EM>Control</EM> <EM>Sequences</EM> as a feature
+ originating with <STRONG>xterm</STRONG>.
+
+ <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 <STRONG>xterm</STRONG>,
+ 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
+ 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
+ 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.