NAME
xscreensaver-command - control a running xscreensaver process
SYNOPSIS
xscreensaver-command [-display host:display.screen] [-help | -demo |
-prefs | -activate | -deactivate | -cycle | -next | -prev | -select n |
-exit | -restart | -lock | -version | -time | -watch]
DESCRIPTION
The xscreensaver-command program controls a running xscreensaver
process by sending it client-messages.
xscreensaver(1) has a client-server model: the xscreensaver process is
a daemon that runs in the background; it is controlled by other
foreground programs such as xscreensaver-command and
xscreensaver-demo(1).
This program, xscreensaver-command, is a command-line-oriented tool;
the xscreensaver-demo(1). program is a graphical tool.
OPTIONS
xscreensaver-command accepts the following command-line options:
-help Prints a brief summary of command-line options.
-demo This just launches the xscreensaver-demo(1) program, in which
one can experiment with the various graphics hacks available,
and edit parameters.
-demo number
When the -demo option is followed by an integer, it instructs
the xscreensaver daemon to run that hack, and wait for the user
to click the mouse before deactivating (i.e., mouse motion does
not deactivate.) This is the mechanism by which
xscreensaver-demo(1) communicates with the xscreensaver(1)
daemon. (The first hack in the list is numbered 1, not 0.)
-prefs Like the no-argument form of -demo, but brings up that
program’s Preferences panel by default.
-activate
Tell xscreensaver to turn on immediately (that is, blank the
screen, as if the user had been idle for long enough.) The
screensaver will deactivate as soon as there is any user
activity, as usual.
It is useful to run this from a menu; you may wish to run it as
sleep 5 ; xscreensaver-command -activate
to be sure that you have time to take your hand off the mouse
before the screensaver comes on. (Because if you jiggle the
mouse, xscreensaver will notice, and deactivate.)
-deactivate
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 -deactivate command periodically is one way to
prevent the screen from blanking.)
-cycle If the screensaver is active (the screen is blanked), then stop
the current graphics demo and run a new one (chosen randomly.)
-next This is like either -activate or -cycle, depending on which is
more appropriate, except that the graphics hack that will be
run is the next one in the list, instead of a randomly-chosen
one. In other words, repeatedly executing -next will cause the
xscreensaver process to invoke each graphics demo sequentially.
(Though using the -demo option is probably an easier way to
accomplish that.)
-prev This is like -next, but cycles in the other direction.
-select number
Like -activate, but runs the Nth element in the list of hacks.
By knowing what is in the programs list, and in what order, you
can use this to activate the screensaver with a particular
graphics demo. (The first element in the list is numbered 1,
not 0.)
-exit Causes the xscreensaver process to exit gracefully. This does
nothing if the display is currently locked.
Warning: never use kill -9 with xscreensaver while the
screensaver is active. If you are using a virtual root window
manager, that can leave things in an inconsistent state, and
you may need to restart your window manager to repair the
damage.
-lock Tells the running xscreensaver process to lock the screen
immediately. This is like -activate, but forces locking as
well, even if locking is not the default (that is, even if
xscreensaver’s lock resource is false, and even if the
lockTimeout resource is non-zero.)
Note that locking doesn’t work unless the xscreensaver process
is running as you. See xscreensaver(1) for details.
-version
Prints the version of xscreensaver that is currently running on
the display: that is, the actual version number of the running
xscreensaver background process, rather than the version number
of xscreensaver-command. (To see the version number of
xscreensaver-command itself, use the -help option.)
-time Prints the time at which the screensaver last activated or
deactivated (roughly, how long the user has been idle or non-
idle: but not quite, since it only tells you when the screen
became blanked or un-blanked.)
-restart
Causes the screensaver process to exit and then restart with
the same command line arguments as last time. You shouldn’t
really need to do this, since xscreensaver notices when the
.xscreensaver file has changed and re-reads it as needed.
-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:
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
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
-select command.)
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 -watch command
and reacts accordingly:
#!/usr/bin/perl
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;
}
}
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.
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:
xset dpms force off
See the xset(1) manual for more info.
You can also use 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.
DIAGNOSTICS
If an error occurs while communicating with the xscreensaver daemon, or
if the daemon reports an error, a diagnostic message will be printed to
stderr, and xscreensaver-command will exit with a non-zero value. If
the command is accepted, an indication of this will be printed to
stdout, and the exit value will be zero.
ENVIRONMENT
DISPLAY to get the host and display number of the screen whose saver is
to be manipulated.
PATH to find the executable to restart (for the -restart command).
Note that this variable is consulted in the environment of the
xscreensaver process, not the xscreensaver-command process.
UPGRADES
The latest version of xscreensaver(1) and related tools can always be
found at http://www.jwz.org/xscreensaver/
SEE ALSO
X(1), xscreensaver(1), xscreensaver-demo(1), xset(1)
COPYRIGHT
Copyright © 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 both that copyright notice and this permission
notice appear in supporting documentation. No representations are made
about the suitability of this software for any purpose. It is provided
"as is" without express or implied warranty.
AUTHOR
Jamie Zawinski <jwz@jwz.org>, 13-aug-92.
Please let me know if you find any bugs or make any improvements.