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	 en‐
       try 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 sta‐
		tus.

       -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 included 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 ex‐
       tension 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	men‐
	   tion	 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 reorganizing 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)