clear(1)                                              General Commands Manual                                              clear(1)

       clear - clear the terminal screen

       clear [-Ttype] [-V] [-x]

       clear  clears  your  terminal's screen if this is possible, including the terminal's scrollback buffer (if the extended “E3”
       capability is defined).  clear looks in the environment for the terminal type given by the environment  variable  TERM,  and
       then in the terminfo database to determine how to clear the screen.

       clear  writes  to  the  standard output.  You can redirect the standard output to a file (which prevents clear from actually
       clearing the screen), and later cat the file to the screen, clearing it at that point.

       -T type
            indicates the type of terminal.  Normally this option is unnecessary, because the default is taken from the environment
            variable TERM.  If -T is specified, then the shell variables LINES and COLUMNS will also be ignored.

       -V   reports the version of ncurses which was used in this program, and exits.  The options are as follows:

       -x   do not attempt to clear the terminal's scrollback buffer using the extended “E3” capability.

       A clear 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 (tset) to make a new command (tput), and used this to replace the clear command with a
       shell script which calls tput clear, e.g.,

           /usr/bin/tput ${1:+-T$1} clear 2> /dev/null

       In 1989, when Keith Bostic revised the BSD tput command to make it similar to the AT&T tput, he added a shell script for the
       clear command:

           exec tput clear

       The remainder of the script in each case is a copyright notice.

       The ncurses clear command began in 1995 by adapting the original BSD clear command (with terminfo, of course).

       The E3 extension came later:

       •   In  June 1999, xterm provided an extension to the standard control sequence for clearing the screen.  Rather than clear‐
           ing just the visible part of the screen using

               printf '\033[2J'

           one could clear the scrollback using

               printf '\033[3J'

           This is documented in XTerm Control Sequences as a feature originating with xterm.

       •   A few other terminal developers adopted the feature, e.g., PuTTY in 2006.

       •   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 re‐
           port (#683733) which led to the change.

       •   Again, a few other terminal developers adopted the feature.  But the next relevant step was a change to the  clear  pro‐
           gram in 2013 to incorporate this extension.

       •   In 2013, the E3 extension was overlooked in tput with the “clear” parameter.  That was addressed in 2016 by reorganizing
           tput to share its logic with clear and tset.

       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 tput, which could be used to replace this utility either via a shell script or by an alias (such as a
       symbolic link) to run tput as clear.

       tput(1), terminfo(5), xterm(1).

       This describes ncurses version 6.4 (patch 20221231).