X-Git-Url: http://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Fclear.1.html;h=74b53fdc670bac6f876f7373d5664c4584df21ac;hp=6215331ecc7ada7813149ed249d0cce731ae08aa;hb=5461fc336d03fbfea6b85ac21c6d49c528f6752d;hpb=02f02dcd4464143580e783ae32c822d8eb8cdcbf
diff --git a/doc/html/man/clear.1.html b/doc/html/man/clear.1.html
index 6215331e..74b53fdc 100644
--- a/doc/html/man/clear.1.html
+++ b/doc/html/man/clear.1.html
@@ -1,6 +1,6 @@
@@ -45,33 +47,107 @@
-
-
+
clear - clear the terminal screen
-
-
+
clear
-
-
+
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 and then in the terminfo database to determine how to
- clear the screen.
+ 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 actu-
+ ally clearing the screen), and later cat the file to the
+ screen, clearing it at that point.
clear ignores any command-line parameters that may be
- present.
+ present. The analogous "tput clear" has command-line
+ parameters including -T for overriding the TERM environ-
+ ment variable.
-
-
+
+ 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:
+
+ o In June 1999, xterm provided an extension to the stan-
+ dard 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.
+
+ 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 exten-
+ sion.
+
+ 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 Specifica-
+ tions 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 6.0 (patch 20150808).
+ This describes ncurses version 6.0 (patch 20161231).
@@ -82,6 +158,8 @@
NAME
SYNOPSIS
DESCRIPTION
+HISTORY
+PORTABILITY
SEE ALSO