Tribblix: manual page: xscreensaver-command.1

XScreenSaver(1) User Commands XScreenSaver(1)

NAME

xscreensaver-command - control a running xscreensaver process

SYNOPSIS

DESCRIPTION

The xscreensaver-command program controls a running xscreensaver(1)
daemon.

OPTIONS

xscreensaver-command accepts the following command-line options:

--help Prints a brief summary of command-line options.

--quiet Only print output if an error occurs.

--verbose
Opposite of --quiet. 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.

--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 --settings 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.)

--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.

--suspend
Like --activate, but ignores lockTimeout and immediately
powers off the screen without fading out. This is intended
to be run just after your laptop's lid is closed, and just
before the CPU halts, to lock things down quickly.

--exit Causes the xscreensaver process to exit gracefully. This
does nothing if the display is currently locked. Warning:
never use kill -9 with xscreensaver. That can leave things
in an inconsistent state, and you may need to log out to
repair the damage.

--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.

--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.)

--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 (my $in, "xscreensaver-command -watch |") || die;
while (<$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.

--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.)

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-settings(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 https://www.jwz.org/xscreensaver/

COPYRIGHT

Copyright (C) 1992-2022 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>.

Please let me know if you find any bugs or make any improvements.

X Version 11 6.09 (07-Jun-2024) XScreenSaver(1)