gclear(1) User Commands gclear(1)

gclear - clear the terminal screen

gclear [-Ttype] [-V] [-x]

gclear clears your terminal's screen if this is possible, including the terminal's scrollback buffer (if the extended “E3” capability is defined). gclear 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.

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

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

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

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 gtput as gclear.

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

This describes ncurses version 6.4 (patch 20221231).

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