Provided by: xscreensaver_6.02+dfsg1-2ubuntu2_amd64 bug

NAME

       xscreensaver-command - control a running xscreensaver process

SYNOPSIS

       xscreensaver-command  [--display  host:display.screen]  [--help  |  --quiet  | --verbose |
       --activate | --deactivate | --cycle | --next | --prev | --select n | --lock | --suspend  |
       --exit | --restart | --time | --watch | --version]

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.

               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 --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 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.

       --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/

SEE ALSO

       X(1), xscreensaver(1), xscreensaver-settings(1), xset(1)

COPYRIGHT

       Copyright © 1992-2021 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-1992.

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