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 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 extension came later.

     o   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.

     o   A few other terminal emulators adopted it, such as PuTTY in 2006.

     o   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.

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

     o   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 6.5                       2025-04-05                          clear(1)