Manual: clear

clear(1)						User commands						    clear(1)

NAME
       clear - clear the terminal screen

SYNOPSIS
       clear [-x] [-T terminal-type]

       clear -V

DESCRIPTION
       clear  clears  your  terminal's screen and its scrollback buffer, if any.  clear retrieves the terminal type from the
       environment variable TERM, then consults the terminfo 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
       user-defined capability, applying an extension mechanism introduced in ncurses 5.0 (1999).

OPTIONS
       clear recognizes the following options.

       -T type	produces  instructions	suitable  for  the terminal type.  Normally, this option is unnecessary, because the
		terminal type is inferred from the environment variable TERM.  If this option is  specified,  clear  ignores
		the environment variables LINES and COLUMNS as well.

       -V	reports the version of ncurses associated with this program and exits with a successful status.

       -x	prevents clear from attempting to clear the scrollback buffer.

PORTABILITY
       Neither IEEE Std 1003.1/The Open Group Base Specifications Issue 7 (POSIX.1-2008) nor X/Open Curses Issue 7 documents
       clear.

       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.

HISTORY
       A clear command using the termcap database and library appeared in 2BSD (1979).	Eighth Edition Unix (1985) later in‐
       cluded it.

       The  commercial Unix arm of AT&T adapted a different BSD program (tset) to make a new command, tput, and replaced the
       clear program with a shell script that called “tput clear”.

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

       In 1989, when Keith Bostic revised the BSD tput command to make it similar to AT&T's tput, he  added  a	clear  shell
       script as well.

	   exec tput clear

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

       In  1995,  ncurses's  clear  began  by  adapting BSD's original clear command to use terminfo.  The E3 extension came
       later.

       •   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'

	   one could clear the scrollback buffer as well by using

	       printf '\033[3J'

	   instead.  “XTerm Control Sequences” documents this feature as originating with xterm.

       •   A few other terminal emulators adopted it, such as 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.	Documentation of this change, appearing in Linux 3.0, did not mention xterm, although  that  program
	   was cited in the Red Hat bug report (#683733) motivating the feature.

       •   Subsequently,  more	terminal  developers  adopted the feature.  The next relevant step was to change the ncurses
	   clear program in 2013 to incorporate this extension.

       •   In 2013, the E3 capability was not exercised by “tput clear”.  That oversight was addressed in 2016 by reorganiz‐
	   ing tput to share its logic with clear and tset.

SEE ALSO
       tput(1), xterm(1), terminfo(5)

ncurses 6.6						 2025-04-05						    clear(1)