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clear(1)                               General Commands Manual                              clear(1)



NAME
       clear - clear the terminal screen

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

DESCRIPTION
       clear  clears  your  screen  if this is possible, including its scrollback buffer (if the ex‐
       tended “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.

OPTIONS
       -T type
            indicates the type of terminal.  Normally this option is unnecessary,  because  the  de‐
            fault  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” capa‐
            bility.

HISTORY
       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
           exit

       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 ter‐
       minfo, 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 clearing 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 report (#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 program 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.

PORTABILITY
       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.

SEE ALSO
       tput(1), terminfo(5)

       This describes ncurses version 6.3 (patch 20211021).



                                                                                            clear(1)