X-Git-Url: https://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Fclear.1.html;h=98cdf7980980b7bf103b29a9fcd262b16c096cbf;hp=d0e7900677bbf7ee6fb7a1c70acc7ca990f9c33a;hb=cb4427a16794d98049b4d790b810d62217501f9f;hpb=46722468f47c2b77b3987729b4bcf2321cccfd01 diff --git a/doc/html/man/clear.1.html b/doc/html/man/clear.1.html index d0e79006..98cdf798 100644 --- a/doc/html/man/clear.1.html +++ b/doc/html/man/clear.1.html @@ -1,7 +1,6 @@ - +
+ +- - --
- clear - clear the terminal screen - - --
- clear - - --
- clear clears your screen if this is possible. It looks in - the environment for the terminal type and then in the ter- - minfo database to figure out how to clear the screen. - - --
- tput(1), terminfo(5) - +clear(1) General Commands Manual clear(1) +
+ clear - clear the terminal screen +
+ clear [-Ttype] [-V] [-x] +
+ clear clears your screen if this is possible, including its scrollback + buffer (if the extended "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. +
+ -T type + indicates the type of terminal. Normally this option is unneces- + sary, because the default is taken from the environment variable + TERM. If -T is specified, then the shell variables LINES and COL- + UMNS 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" 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 sim- + ilar 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: + 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 using + printf '\033[3J' + This is documented in XTerm Control Sequences as a feature origi- + nating with xterm. + o A few other terminal developers adopted the feature, e.g., 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. 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. + o 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. + o 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. +
+ 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. +
+ tput(1), terminfo(5) + This describes ncurses version 6.1 (patch 20190316). + clear(1)-