.if n .sp 1
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-.TH XScreenSaver 1 "22-Nov-98 (3.06)" "X Version 11"
+.TH XScreenSaver 1 "20-Mar-2005 (4.21)" "X Version 11"
.SH NAME
xscreensaver-command - control a running xscreensaver process
.SH SYNOPSIS
.B xscreensaver-command
-[\-help] \
-[\-demo] \
-[\-prefs] \
-[\-activate] \
-[\-deactivate] \
-[\-cycle] \
-[\-next] \
-[\-prev] \
-[\-select \fIn\fP] \
-[\-exit] \
-[\-restart] \
-[\-lock] \
-[\-version] \
-[\-time]
+[\-display \fIhost:display.screen\fP] \
+[\-help | \
+\-demo | \
+\-prefs | \
+\-activate | \
+\-deactivate | \
+\-cycle | \
+\-next | \
+\-prev | \
+\-select \fIn\fP | \
+\-exit | \
+\-restart | \
+\-lock | \
+\-version | \
+\-time | \
+\-watch]
.SH DESCRIPTION
The \fIxscreensaver\-command\fP program controls a running \fIxscreensaver\fP
process by sending it client-messages.
will notice, and deactivate.)
.TP 8
.B \-deactivate
-If the screensaver is active (the screen is blanked), this command will
-deactivate it just as if there had been keyboard or mouse activity.
-If locking is enabled, then the screensaver will prompt for a password
-as usual.
+This tells xscreensaver to pretend that there has just been user activity.
+This means that if the screensaver is active (the screen is blanked),
+then this command will cause the screen to un-blank as if there had been
+keyboard or mouse activity. If the screen is locked, then the password
+dialog will pop up first, as usual. If the screen is not blanked, then
+this simulated user activity will re-start the countdown (so, issuing
+the \fI\-deactivate\fP command periodically is \fIone\fP way to prevent
+the screen from blanking.)
.TP 8
.B \-cycle
If the screensaver is active (the screen is blanked), then stop the current
element in the list is numbered 1, not 0.)
.TP 8
.B \-exit
-Causes the xscreensaver process to exit gracefully. This is roughly the same
-as killing the process with
-.BR kill (1),
-but it is easier, since you don't need to first figure out the pid.
+Causes the xscreensaver process to exit gracefully.
+This does nothing if the display is currently locked.
.B Warning:
never use \fIkill -9\fP with \fIxscreensaver\fP while the screensaver is
.TP 8
.B \-restart
Causes the screensaver process to exit and then restart with the same command
-line arguments as last time. Do this after you've changed the resource
-database, to cause xscreensaver to notice the changes.
+line arguments as last time. You shouldn't really need to do this,
+since xscreensaver notices when the \fI.xscreensaver\fP file has
+changed and re-reads it as needed.
+.TP 8
+.B \-watch
+Prints a line each time the screensaver changes state: when the screen
+blanks, locks, unblanks, or when the running hack is changed. This option
+never returns; it is intended for use by shell scripts that want to react to
+the screensaver in some way. An example of its output would be:
+.EX
+BLANK Fri Nov 5 01:57:22 1999
+RUN 34
+RUN 79
+RUN 16
+LOCK Fri Nov 5 01:57:22 1999
+RUN 76
+RUN 12
+UNBLANK Fri Nov 5 02:05:59 1999
+.EE
+The above shows the screensaver activating, running three different
+hacks, then locking (perhaps because the lock-timeout went off) then
+unblanking (because the user became active, and typed the correct
+password.) The hack numbers are their index in the `programs'
+list (starting with 1, not 0, as for the \fI\-select\fP command.)
-.B Warning:
-if you have a \fI.xscreensaver\fP file, this might not do what you
-expect. You're probably better off killing the existing
-xscreensaver (with \fIxscreensaver\-command -exit\fP) and then
-launching it again.
+For example, suppose you want to run a program that turns down the volume
+on your machine when the screen blanks, and turns it back up when the screen
+un-blanks. You could do that by running a Perl program like the following
+in the background. The following program tracks the output of
+the \fI\-watch\fP command and reacts accordingly:
+.EX
+#!/usr/bin/perl
-The important point is, you need to make sure that the xscreensaver
-process is running as you. If it's not, it won't be reading the
-right \fI.xscreensaver\fP file.
+my $blanked = 0;
+open (IN, "xscreensaver-command -watch |");
+while (<IN>) {
+ if (m/^(BLANK|LOCK)/) {
+ if (!$blanked) {
+ system "sound-off";
+ $blanked = 1;
+ }
+ } elsif (m/^UNBLANK/) {
+ system "sound-on";
+ $blanked = 0;
+ }
+}
+.EE
+Note that LOCK might come either with or without a preceding BLANK
+(depending on whether the lock-timeout is non-zero), so the above program
+keeps track of both of them.
+.SH STOPPING GRAPHICS
+If xscreensaver is running, but you want it to stop running screen hacks
+(e.g., if you are logged in remotely, and you want the console to remain
+locked but just be black, with no graphics processes running) you can
+accomplish that by simply powering down the monitor remotely. In a
+minute or so, xscreensaver will notice that the monitor is off, and
+will stop running screen hacks. You can power off the monitor like so:
+.EX
+xset dpms force off
+.EE
+See the
+.BR xset (1)
+manual for more info.
+
+You can also use
+.BR xscreensaver-demo (1)
+to make the monitor power down after a few hours, meaning that xscreensaver
+will run graphics until it has been idle for the length of time you
+specified; and after that, the monitor will power off, and screen hacks
+will stop being run.
.SH DIAGNOSTICS
If an error occurs while communicating with the \fIxscreensaver\fP daemon, or
if the daemon reports an error, a diagnostic message will be printed to
and related tools can always be found at http://www.jwz.org/xscreensaver/
.SH "SEE ALSO"
.BR X (1),
-.BR xscreensaver (1)
-.BR xscreensaver\-demo (1)
+.BR xscreensaver (1),
+.BR xscreensaver\-demo (1),
+.BR xset (1)
.SH COPYRIGHT
-Copyright \(co 1992, 1993, 1997, 1998
+Copyright \(co 1992, 1993, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
by Jamie Zawinski. Permission to use, copy, modify, distribute, and sell
this software and its documentation for any purpose is hereby granted without
fee, provided that the above copyright notice appear in all copies and that
projects / xscreensaver / blobdiff