Provided by: xscreensaver_5.14-1ubuntu1_i386 bug

NAME

       xscreensaver - extensible screen saver framework, plus locking

SYNOPSIS

       xscreensaver  [-display  host:display.screen]  [-verbose]  [-no-splash]
       [-no-capture-stderr] [-log filename]

DESCRIPTION

       The xscreensaver program waits until the keyboard and mouse  have  been
       idle  for a period, and then runs a graphics demo chosen at random.  It
       turns off as soon as there is any mouse or keyboard activity.

       This program can lock your terminal in order  to  prevent  others  from
       using  it,  though  its  default mode of operation is merely to display
       pretty pictures on your screen when it is not in use.

       It also provides configuration and control  of  your  monitor's  power-
       saving features.

GETTING STARTED

       For the impatient, try this:
       xscreensaver &
       xscreensaver-demo
       The  xscreensaver-demo(1)  program  pops  up a dialog box that lets you
       configure the screen saver, and experiment  with  the  various  display
       modes.

       Note  that  xscreensaver  has  a  client-server model: the xscreensaver
       program is a daemon that runs in the background; it  is  controlled  by
       the   foreground   xscreensaver-demo(1)   and   xscreensaver-command(1)
       programs.

CONFIGURATION

       The easiest  way  to  configure  xscreensaver  is  to  simply  run  the
       xscreensaver-demo(1)  program, and change the settings through the GUI.
       The rest of this manual page describes lower  level  ways  of  changing
       settings.

       I'll repeat that because it's important:

           The  easy way to configure xscreensaver is to run the xscreensaver-
           demo(1) program.  You shouldn't need  to  know  any  of  the  stuff
           described  in  this  manual  unless  you are trying to do something
           tricky, like customize xscreensaver for site-wide use or something.

       Options to  xscreensaver  are  stored  in  one  of  two  places:  in  a
       .xscreensaver  file  in  your  home  directory;  or  in  the X resource
       database.  If the .xscreensaver file exists, it overrides any  settings
       in the resource database.

       The  syntax  of  the  .xscreensaver  file  is  similar  to  that of the
       .Xdefaults file; for example,  to  set  the  timeout  paramter  in  the
       .xscreensaver file, you would write the following:
       timeout: 5
       whereas, in the .Xdefaults file, you would write
       xscreensaver.timeout: 5
       If you change a setting in the .xscreensaver file while xscreensaver is
       already running, it will notice this, and reload the file.   (The  file
       will  be  reloaded  the  next  time the screen saver needs to take some
       action, such as blanking or unblanking the screen,  or  picking  a  new
       graphics mode.)

       If  you  change  a  setting in your X resource database, or if you want
       xscreensaver to notice your changes immediately  instead  of  the  next
       time  it  wakes  up, then you will need to reload your .Xdefaults file,
       and then tell the running xscreensaver process to restart itself,  like
       so:
       xrdb < ~/.Xdefaults
       xscreensaver-command -restart
       If  you  want  to set the system-wide defaults, then make your edits to
       the xscreensaver app-defaults file, which should  have  been  installed
       when  xscreensaver  itself  was  installed.  The app-defaults file will
       usually be named /usr/lib/X11/app-defaults/XScreenSaver, but  different
       systems   might   keep   it   in   a   different  place  (for  example,
       /usr/openwin/lib/app-defaults/XScreenSaver on Solaris.)

       When settings are changed in the Preferences dialog box (see above) the
       current  settings  will  be  written  to  the .xscreensaver file.  (The
       .Xdefaults file and the app-defaults file  will  never  be  written  by
       xscreensaver itself.)

COMMAND-LINE OPTIONS

       xscreensaver  also  accepts  a few command-line options, mostly for use
       when debugging: for normal operation, you should configure  things  via
       the ~/.xscreensaver file.

       -display host:display.screen
               The  X  display  to  use.   For displays with multiple screens,
               XScreenSaver  will  manage   all   screens   on   the   display
               simultaniously.

       -verbose
               Same as setting the verbose resource to true: print diagnostics
               on stderr and on the xscreensaver window.

       -no-capture-stderr
               Do  not  redirect  the  stdout  and  stderr  streams   to   the
               xscreensaver  window  itself.  If xscreensaver is crashing, you
               might need to do this in order to see the error message.

       -log filename
               This is exactly the same as redirecting stdout  and  stderr  to
               the  given  file  (for  append).  This is useful when reporting
               bugs.

HOW IT WORKS

       When it is time to activate the screensaver, a full-screen black window
       is  created  on  each screen of the display.  Each window is created in
       such a way that, to any subsequently-created programs, it  will  appear
       to  be  a  ``virtual root'' window.  Because of this, any program which
       draws on the root window (and which understands virtual roots)  can  be
       used  as  a screensaver.  The various graphics demos are, in fact, just
       standalone programs that know how to draw on the provided window.

       When the  user  becomes  active  again,  the  screensaver  windows  are
       unmapped,  and  the  running  subprocesses  are  killed by sending them
       SIGTERM.  This is  also  how  the  subprocesses  are  killed  when  the
       screensaver decides that it's time to run a different demo: the old one
       is killed and a new one is launched.

       You  can  control  a  running  screensaver   process   by   using   the
       xscreensaver-command(1) program (which see.)

POWER MANAGEMENT

       Modern  X  servers  contain  support to power down the monitor after an
       idle period.  If the monitor has powered down, then  xscreensaver  will
       notice  this  (after  a few minutes), and will not waste CPU by drawing
       graphics demos on a black screen.  An attempt  will  also  be  made  to
       explicitly  power  the  monitor  back  up  as  soon as user activity is
       detected.

       The ~/.xscreensaver file controls the configuration of  your  display's
       power  management  settings:  if  you  have used xset(1) to change your
       power  management  settings,  then  xscreensaver  will  override  those
       changes  with  the  values  specified  in  ~/.xscreensaver (or with its
       built-in defaults, if there is no ~/.xscreensaver file yet.)

       To change your power management settings, run xscreensaver-demo(1)  and
       change  the  various timeouts through the user interface.  Alternately,
       you can edit the ~/.xscreensaver file directly.

       If   the   power   management   section   is   grayed   out   in    the
       xscreensaver-demo(1)  window,   then that means that your X server does
       not support the XDPMS extension, and  so  control  over  the  monitor's
       power state is not available.

       If  you're  using  a  laptop,  don't  be surprised if changing the DPMS
       settings has no effect: many laptops have monitor power-saving behavior
       built  in at a very low level that is invisible to Unix and X.  On such
       systems, you can typically  adjust  the  power-saving  delays  only  by
       changing settings in the BIOS in some hardware-specific way.

       If  DPMS  seems  not  to  be working with XFree86, make sure the "DPMS"
       option is set in your /etc/X11/XF86Config file.  See the  XF86Config(5)
       manual for details.

USING GNOME

       For  many  years, GNOME shipped xscreensaver as-is, and everything just
       worked out of the box.  Recently, however,  they've  been  re-inventing
       the wheel again in the form of "gnome-screensaver".

       To replace gnome-screensaver with xscreensaver:

           1: Turn off gnome-screensaver.
              Open  ``System  /  Preferences  / Screensaver'' and uncheck both
              boxes.

           2: Stop gnome-screensaver from launching at login.
              Run the command:
              gconftool-2 --type boolean -s \
              /apps/gnome_settings_daemon/screensaver/start_screensaver \
              false
              Or, just uninstall the "gnome-screensaver" package entirely.

           3: Launch xscreensaver at login.
              Open ``System / Preferences /  Sessions  /  Startup  Programs''.
              Click ``Add'' and type ``xscreensaver''.

           4: Tell Preferences to use the xscreensaver configurator.
              Edit                  /usr/share/applications/gnome-screensaver-
              preferences.desktop and change the Exec= line to say
                  Exec=xscreensaver-demo

           5: Make ``System / Quit / Lock Screen'' use xscreensaver.
              Run the command:
              sudo ln -sf /usr/bin/xscreensaver-command \
                          /usr/bin/gnome-screensaver-command

USING KDE

       KDE also has invented their  own  screen  saver  framework  instead  of
       simply  using  xscreensaver.   To  replace  the  KDE  screen saver with
       xscreensaver, do the following:

           1: Turn off KDE's screen saver.
              Open the ``Control Center'' and select the ``Appearance & Themes
              / Screensaver'' page.  Un-check ``Start Automatically''.

           2: Find your Autostart directory.
              Open  the  ``System Administration -> Paths'' page, and see what
              your  ``Autostart  path''  is  set  to:  it  will  probably   be
              ~/.kde/Autostart/ or something similar.

           3: Make xscreensaver be an Autostart program.
              Create  a  .desktop  file  in  your  autostart  directory called
              xscreensaver.desktop that contains the following five lines:
              [Desktop Entry]
              Exec=xscreensaver
              Name=XScreenSaver
              Type=Application
              X-KDE-StartupNotify=false

           4: Make the various "lock session" buttons call xscreensaver.
              Replace the file kdesktop_lock or krunner_lock or  kscreenlocker
              in  /usr/bin/  (or  possibly in /usr/kde/3.5/bin/ or possibly in
              /usr/lib/kde4/libexec/ or /usr/libexec/kde4/, depending  on  the
              distro and phase of the moon) with these two lines:
              #!/bin/sh
              xscreensaver-command -lock
              Make sure the file is executable (chmod a+x).

       Now   use   xscreensaver   normally,   controlling  it  via  the  usual
       xscreensaver-demo(1) and xscreensaver-command(1) mechanisms.

USING GDM

       You can  run  xscreensaver  from  your  gdm(1)  session,  so  that  the
       screensaver  will run even when nobody is logged in on the console.  To
       do this, run gdmconfig(1) and on the Background page, type the  command
       "xscreensaver  -nosplash" into the Background Program field.  That will
       cause gdm to run xscreensaver while nobody is logged in, and kill it as
       soon  as  someone  does log in.  (The user will then be responsible for
       starting xscreensaver on their own, if they want.)

       Another  way  to  accomplish  the  same  thing  is  to  edit  the  file
       /etc/X11/gdm/gdm.conf to include:
       BackgroundProgram=xscreensaver -nosplash
       RunBackgroundProgramAlways=true
       In this situation, the xscreensaver process will probably be running as
       user gdm instead of root.  You can  configure  the  settings  for  this
       nobody-logged-in   state   (timeouts,   DPMS,   etc.)  by  editing  the
       ~gdm/.xscreensaver file.

       To get gdm to run the BackgroundProgram, you may need to switch it from
       the "Graphical Greeter" to the "Standard Greeter".

       It  is  safe  to run xscreensaver as root (as xdm is likely to do.)  If
       run as root, xscreensaver changes its effective user and group  ids  to
       something  safe  (like  "nobody")  before connecting to the X server or
       launching user-specified programs.

       An unfortunate side effect of this (important) security  precaution  is
       that it may conflict with cookie-based authentication.

       If  you  get "connection refused" errors when running xscreensaver from
       gdm, then this probably means that you  have  xauth(1)  or  some  other
       security mechanism turned on.  For information on the X server's access
       control mechanisms, see the man pages for X(1), Xsecurity(1), xauth(1),
       and xhost(1).

BUGS

       Bugs?   There  are  no bugs.  Ok, well, maybe.  If you find one, please
       let me know.  http://www.jwz.org/xscreensaver/bugs.html explains how to
       construct the most useful bug reports.

       Locking and XDM
               If xscreensaver has been launched from xdm(1) before anyone has
               logged  in,  you  will  need  to  kill  and  then  restart  the
               xscreensaver  daemon  after  you have logged in, or you will be
               confused by the results.  (For example, locking won't work, and
               your ~/.xscreensaver file will be ignored.)

               When  you are logged in, you want the xscreensaver daemon to be
               running under your user id, not as root or some other user.

               If it has already been started by  xdm,  you  can  kill  it  by
               sending  it  the exit command, and then re-launching it as you,
               by putting something like the  following  in  your  personal  X
               startup script:
               xscreensaver-command -exit
               xscreensaver &
               The ``Using XDM(1)'' section, above, goes into more detail, and
               explains how to configure the system to do this for  all  users
               automatically.

       Locking and root logins
               In  order  for it to be safe for xscreensaver to be launched by
               xdm, certain precautions had  to  be  taken,  among  them  that
               xscreensaver  never  runs  as  root.   In  particular, if it is
               launched as root (as xdm is likely to  do),  xscreensaver  will
               disavow  its  privileges,  and  switch itself to a safe user id
               (such as nobody.)

               An implication of this is that if you log in  as  root  on  the
               console,  xscreensaver  will refuse to lock the screen (because
               it can't tell the difference between root being  logged  in  on
               the  console,  and a normal user being logged in on the console
               but xscreensaver having been  launched  by  the  xdm(1)  Xsetup
               file.)

               The  solution to this is simple: you shouldn't be logging in on
               the console as root in the first place!  (What, are  you  crazy
               or something?)

               Proper  Unix  hygiene  dictates  that  you  should  log  in  as
               yourself, and su(1) to root as  necessary.   People  who  spend
               their day logged in as root are just begging for disaster.

       XAUTH and XDM
               For  xscreensaver  to  work  when  launched by xdm(1), programs
               running on the local machine as user "nobody" must be  able  to
               connect  to  the  X server.  This means that if you want to run
               xscreensaver on the console while nobody is logged in, you  may
               need  to  disable  cookie-based  access  control (and allow all
               users who can log in to the local machine  to  connect  to  the
               display.)

               You  should  be  sure that this is an acceptable thing to do in
               your environment before doing it.   See  the  ``Using  XDM(1)''
               section, above, for more details.

       Passwords
               If  you  get  an  error  message at startup like ``couldn't get
               password of user'' then this probably means that  you're  on  a
               system  in  which  the  getpwent(3) library routine can only be
               effectively  used  by  root.   If  this  is  the   case,   then
               xscreensaver  must  be installed as setuid to root in order for
               locking to work.  Care has been taken to make this a safe thing
               to do.

               It also may mean that your system uses shadow passwords instead
               of the standard getpwent(3) interface; in that  case,  you  may
               need to change some options with configure and recompile.

               If  you  change  your  password  after  xscreensaver  has  been
               launched, it will continue using your old  password  to  unlock
               the  screen  until xscreensaver is restarted.  On some systems,
               it may accept both your old and new passwords.  So,  after  you
               change your password, you'll have to do
               xscreensaver-command -restart
               to make xscreensaver notice.

       PAM Passwords
               If  your  system  uses  PAM (Pluggable Authentication Modules),
               then in order for xscreensaver to use PAM properly, PAM must be
               told about xscreensaver.  The xscreensaver installation process
               should update the PAM data (on  Linux,  by  creating  the  file
               /etc/pam.d/xscreensaver for you, and on Solaris, by telling you
               what lines to add to the /etc/pam.conf file.)

               If the PAM configuration files do not know about  xscreensaver,
               then you might be in a situation where xscreensaver will refuse
               to ever unlock the screen.

               This is a design flaw in PAM (there is no way for a  client  to
               tell the difference between PAM responding ``I have never heard
               of  your  module,''  and  responding,  ``you  typed  the  wrong
               password.'')   As  far  as  I  can  tell,  there  is no way for
               xscreensaver to automatically work around this, or  detect  the
               problem  in  advance,  so  if  you  have  PAM,  make sure it is
               configured correctly!

       Machine Load
               Although  this  program  ``nices''  the  subprocesses  that  it
               starts,  graphics-intensive  subprograms can still overload the
               machine by causing the X server process itself  (which  is  not
               ``niced'')  to consume many cycles.  Care has been taken in all
               the modules shipped with xscreensaver  to  sleep  periodically,
               and not run full tilt, so as not to cause appreciable load.

               However, if you are running the OpenGL-based screen savers on a
               machine that does not have a video card with  3D  acceleration,
               they will make your machine slow, despite nice(1).

               Your  options  are:  don't  use  the  OpenGL display modes; or,
               collect the spare change hidden  under  the  cushions  of  your
               couch,  and use it to buy a video card manufactured after 1998.
               (It doesn't even need to be fast 3D hardware: the problem  will
               be fixed if there is any 3D hardware at all.)

       XFree86's Magic Keystrokes
               The  XFree86  X  server  traps  certain magic keystrokes before
               client programs ever see  them.   Two  that  are  of  note  are
               Ctrl+Alt+Backspace,  which  causes  the  X  server to exit; and
               Ctrl+Alt+Fn, which switches virtual  consoles.   The  X  server
               will  respond  to these keystrokes even if xscreensaver has the
               screen locked.  Depending on your  setup,  you  might  consider
               this a problem.

               Unfortunately,  there  is  no  way  for  xscreensaver itself to
               override the interpretation of these  keys.   If  you  want  to
               disable  Ctrl+Alt+Backspace  globally,  you  need  to  set  the
               DontZap flag in your  /etc/X11/XF86Config  file.   To  globally
               disable  VT  switching, you can set the DontVTSwitch flag.  See
               the XF86Config(5) manual for details.

X RESOURCES

       These are the  X  resources  use  by  the  xscreensaver  program.   You
       probably   won't  need  to  change  these  manually  (that's  what  the
       xscreensaver-demo(1) program is for).

       timeout (class Time)
               The screensaver will activate  (blank  the  screen)  after  the
               keyboard  and  mouse  have  been  idle  for  this many minutes.
               Default 10 minutes.

       cycle (class Time)
               After the screensaver has been running for this  many  minutes,
               the  currently running graphics-hack sub-process will be killed
               (with SIGTERM), and a new one started.  If this is 0, then  the
               graphics  hack  will  never  be changed: only one demo will run
               until the screensaver is deactivated by user activity.  Default
               10 minutes.

       lock (class Boolean)
               Enable  locking:  before the screensaver will turn off, it will
               require you to type the password of the logged-in user (really,
               the person who ran xscreensaver), or the root password.  (Note:
               this doesn't work if the  screensaver  is  launched  by  xdm(1)
               because  it  can't know the user-id of the logged-in user.  See
               the ``Using XDM(1)'' section, below.

       lockTimeout (class Time)
               If locking is enabled, this controls the length of the  ``grace
               period''  between  when the screensaver activates, and when the
               screen becomes locked.  For example, if this is 5, and -timeout
               is 10, then after 10 minutes, the screen would blank.  If there
               was user activity at 12 minutes, no password would be  required
               to  un-blank the screen.  But, if there was user activity at 15
               minutes  or  later  (that  is,  -lock-timeout   minutes   after
               activation)  then a password would be required.  The default is
               0, meaning that if locking is enabled, then a password will  be
               required as soon as the screen blanks.

       passwdTimeout (class Time)
               If  the  screen  is  locked,  then this is how many seconds the
               password dialog box should be left on the screen before  giving
               up  (default  30 seconds.)  This should not be too large: the X
               server is grabbed for the duration that the password dialog box
               is  up  (for  security purposes) and leaving the server grabbed
               for too long can cause problems.

       dpmsEnabled (class Boolean)
               Whether power management is enabled.

       dpmsStandby (class Time)
               If power management is enabled, how long until the monitor goes
               solid black.

       dpmsSuspend (class Time)
               If power management is enabled, how long until the monitor goes
               into power-saving mode.

       dpmsOff (class Time)
               If power management is enabled,  how  long  until  the  monitor
               powers  down completely.  Note that these settings will have no
               effect unless both  the  X  server  and  the  display  hardware
               support power management; not all do.  See the Power Management
               section, below, for more information.

       dpmsQuickOff (class Boolean)
               If mode is blank and this is true,  then  the  screen  will  be
               powered  down  immediately  upon  blanking, regardless of other
               power-management settings.

       visualID (class VisualID)
               Specify which X visual to use by default.  (Note carefully that
               this resource is called visualID, not merely visual; if you set
               the visual resource instead, things will malfunction in obscure
               ways for obscure reasons.)

               Legal values for the VisualID resource are:

               default Use the screen's default visual (the visual of the root
                       window.)  This is the default.

               best    Use the visual which supports the most  colors.   Note,
                       however,  that the visual with the most colors might be
                       a TrueColor visual, which  does  not  support  colormap
                       animation.    Some   programs   have  more  interesting
                       behavior  when  run  on  PseudoColor  visuals  than  on
                       TrueColor.

               mono    Use a monochrome visual, if there is one.

               gray    Use  a  grayscale or staticgray visual, if there is one
                       and it has more than  one  plane  (that  is,  it's  not
                       monochrome.)

               color   Use the best of the color visuals, if there are any.

               GL      Use  the  visual  that  is  best  for  OpenGL programs.
                       (OpenGL programs have somewhat  different  requirements
                       than other X programs.)

               class   where   class   is   one  of  StaticGray,  StaticColor,
                       TrueColor,  GrayScale,  PseudoColor,  or   DirectColor.
                       Selects the deepest visual of the given class.

               number  where  number  (decimal  or  hex)  is  interpreted as a
                       visual  id  number,  as  reported  by  the  xdpyinfo(1)
                       program;  in  this  way you can have finer control over
                       exactly which visual gets used, for example, to  select
                       a shallower one than would otherwise have been chosen.

               Note  that  this  option specifies only the default visual that
               will be used: the visual used may be overridden on  a  program-
               by-program   basis.    See  the  description  of  the  programs
               resource, below.

       installColormap (class Boolean)
               On PseudoColor (8-bit) displays,  install  a  private  colormap
               while the screensaver is active, so that the graphics hacks can
               get as many colors as possible.  This is  the  default.   (This
               only  applies  when  the screen's default visual is being used,
               since   non-default   visuals   get   their    own    colormaps
               automatically.)   This  can  also  be  overridden on a per-hack
               basis: see the discussion of the default-n name in the  section
               about the programs resource.

               This  does  nothing  if you have a TrueColor (16-bit or deeper)
               display.

       verbose (class Boolean)
               Whether to print diagnostics.  Default false.

       timestamp (class Boolean)
               Whether  to  print  the  time  of  day  along  with  any  other
               diagnostic messages.  Default true.

       splash (class Boolean)
               Whether to display a splash screen at startup.  Default true.

       splashDuration (class Time)
               How  long  the  splash  screen should remain visible; default 5
               seconds.

       helpURL (class URL)
               The splash screen has a Help button on it.  When you press  it,
               it  will  display  the  web  page  indicated  here  in your web
               browser.

       loadURL (class LoadURL)
               This is the shell command used to load  a  URL  into  your  web
               browser.     The    default   setting   will   load   it   into
               Mozilla/Netscape if it  is  already  running,  otherwise,  will
               launch a new browser looking at the helpURL.

       demoCommand (class DemoCommand)
               This  is  the  shell  command  run  when the Demo button on the
               splash window is pressed.  It defaults to xscreensaver-demo(1).

       prefsCommand (class PrefsCommand)
               This is the shell command run when  the  Prefs  button  on  the
               splash     window     is     pressed.      It    defaults    to
               xscreensaver-demo -prefs.

       nice (class Nice)
               The sub-processes created by xscreensaver will be ``niced''  to
               this  level,  so  that they are given lower priority than other
               processes  on  the  system,  and  don't   increase   the   load
               unnecessarily.  The default is 10.

               (Higher numbers mean lower priority; see nice(1) for details.)

       fade (class Boolean)
               If  this  is  true,  then  when  the screensaver activates, the
               current contents of the screen will fade to  black  instead  of
               simply  winking  out.   This  only works on certain systems.  A
               fade will also be done when switching graphics hacks (when  the
               cycle timer expires.)  Default: true.

       unfade (class Boolean)
               If  this  is  true,  then when the screensaver deactivates, the
               original contents of the screen will fade in from black instead
               of  appearing immediately.  This only works on certain systems,
               and if fade is true as well.  Default false.

       fadeSeconds (class Time)
               If fade is true, this is how long the fade will be  in  seconds
               (default 3 seconds.)

       fadeTicks (class Integer)
               If  fade  is true, this is how many times a second the colormap
               will be  changed  to  effect  a  fade.   Higher  numbers  yield
               smoother  fades,  but  may  make the fades take longer than the
               specified fadeSeconds if your server isn't fast enough to  keep
               up.  Default 20.

       captureStderr (class Boolean)
               Whether  xscreensaver  should  redirect  its  stdout and stderr
               streams to the window itself.  Since its nature is to take over
               the screen, you would not normally see error messages generated
               by xscreensaver or the sub-programs it runs; this resource will
               cause  the  output  of all relevant programs to be drawn on the
               screensaver window itself, as well  as  being  written  to  the
               controlling   terminal   of  the  screensaver  driver  process.
               Default true.

       ignoreUninstalledPrograms (class Boolean)
               There may be programs in the list that are not installed on the
               system,  yet  are  marked  as "enabled."  If this preference is
               true, then such programs will simply  be  ignored.   If  false,
               then a warning will be printed if an attempt is made to run the
               nonexistent program.  Also,  the  xscreensaver-demo(1)  program
               will  suppress  the non-existent programs from the list if this
               is true.  Default: false.

       GetViewPortIsFullOfLies (class Boolean)
               Set this to true if the xscreensaver window doesn't  cover  the
               whole  screen.   This  works  around a longstanding XFree86 bug
               #421.  See the xscreensaver FAQ for details.

       font (class Font)
               The font used for the stdout/stderr text, if  captureStderr  is
               true.   Default  *-medium-r-*-140-*-m-* (a 14 point fixed-width
               font.)

       mode (class Mode)
               Controls the behavior of xscreensaver.  Legal values are:

               random  When blanking the screen, select a random display  mode
                       from among those that are enabled and applicable.  This
                       is the default.

               random-same
                       Like random, but if there are  multiple  screens,  each
                       screen  will  run the same random display mode, instead
                       of each screen running a different one.

               one     When blanking the screen, only ever use one  particular
                       display   mode  (the  one  indicated  by  the  selected
                       setting.)

               blank   When blanking the screen, just go black: don't run  any
                       graphics hacks.

               off     Don't  ever  blank the screen, and don't ever allow the
                       monitor to power down.

       selected (class Integer)
               When mode is set to one, this is  the  one,  indicated  by  its
               index in the programs list.  You're crazy if you count them and
               set this number by hand: let  xscreensaver-demo(1)  do  it  for
               you!

       programs (class Programs)
               The  graphics  hacks  which  xscreensaver runs when the user is
               idle.  The value of this resource is a multi-line  string,  one
               sh-syntax command per line.  Each line must contain exactly one
               command: no semicolons, no ampersands.

               When the screensaver  starts  up,  one  of  these  is  selected
               (according  to  the  mode  setting),  and run.  After the cycle
               period expires, it is killed, and another is selected and run.

               If a line begins with a dash (-) then that  particular  program
               is  disabled:  it  won't  be selected at random (though you can
               still  select  it  explicitly  using  the  xscreensaver-demo(1)
               program.)

               If all programs are disabled, then the screen will just be made
               blank, as when mode is set to blank.

               To disable a program, you must mark it as disabled with a  dash
               instead  of  removing  it  from  the list.  This is because the
               system-wide   (app-defaults)   and   per-user   (.xscreensaver)
               settings  are  merged  together,  and if a user just deletes an
               entry from their programs list, but that entry still exists  in
               the  system-wide list, then it will come back.  However, if the
               user disables it, then their setting takes precedence.

               If the display has multiple screens, then a  different  program
               will  be  run  for  each  screen.  (All screens are blanked and
               unblanked simultaneously.)

               Note that you must escape the newlines; here is an  example  of
               how you might set this in your ~/.xscreensaver file:

               programs:  \
                      qix -root                          \n\
                      ico -r -faces -sleep 1 -obj ico    \n\
                      xdaliclock -builtin2 -root         \n\
                      xv -root -rmode 5 image.gif -quit  \n
               Make  sure  your $PATH environment variable is set up correctly
               before xscreensaver is launched, or it won't be  able  to  find
               the programs listed in the programs resource.

               To  use  a  program  as a screensaver, two things are required:
               that that program draw on the root window (or  be  able  to  be
               configured  to  draw on the root window); and that that program
               understand ``virtual root'' windows, as used by virtual  window
               managers such as tvtwm(1).  (Generally, this is accomplished by
               just including the  "vroot.h"  header  file  in  the  program's
               source.)

               If there are some programs that you want to run only when using
               a color display, and others that you  want  to  run  only  when
               using a monochrome display, you can specify that like this:
                      mono:   mono-program  -root        \n\
                      color:  color-program -root        \n\
               More  generally, you can specify the kind of visual that should
               be used for the window on which the program  will  be  drawing.
               For  example,  if  one program works best if it has a colormap,
               but another works best if it has a 24-bit visual, both  can  be
               accommodated:
                      PseudoColor: cmap-program  -root   \n\
                      TrueColor:   24bit-program -root   \n\
               In  addition  to  the symbolic visual names described above (in
               the discussion of the visualID resource) one other visual  name
               is supported in the programs list:

                default-n
                    This  is  like  default,  but also requests the use of the
                    default colormap, instead of a  private  colormap.   (That
                    is,  it  behaves as if the -no-install command-line option
                    was specified, but only for this particular  hack.)   This
                    is provided because some third-party programs that draw on
                    the root  window  (notably:  xv(1),  and  xearth(1))  make
                    assumptions  about  the  visual  and  colormap of the root
                    window: assumptions which xscreensaver can violate.

               If you specify a particular visual  for  a  program,  and  that
               visual does not exist on the screen, then that program will not
               be chosen to run.  This means that on  displays  with  multiple
               screens  of  different  depths, you can arrange for appropriate
               hacks to be run on each.  For example, if one screen  is  color
               and  the  other is monochrome, hacks that look good in mono can
               be run on one, and hacks that only look good in color will show
               up on the other.

       You shouldn't ever need to change the following resources:

       pointerPollTime (class Time)
               When  server  extensions  are  not  in  use,  this controls how
               frequently xscreensaver checks to see if the mouse position  or
               buttons have changed.  Default 5 seconds.

       pointerHysteresis (class Integer)
               If  the  mouse  moves  less  than this-many pixels in a second,
               ignore it (do not consider that to be "activity.")  This is  so
               that  the  screen  doesn't  un-blank  (or  fail  to blank) just
               because you bumped the desk.  Default: 10 pixels.

       windowCreationTimeout (class Time)
               When server extensions are not in use, this controls the  delay
               between  when windows are created and when xscreensaver selects
               events on them.  Default 30 seconds.

       initialDelay (class Time)
               When server extensions are not in use, xscreensaver  will  wait
               this  many seconds before selecting events on existing windows,
               under the assumption that xscreensaver is started  during  your
               login  procedure, and the window state may be in flux.  Default
               0.  (This used to default to 30, but that was back in the  days
               when slow machines and X terminals were more common...)

       procInterrupts (class Boolean)
               This resource controls whether the /proc/interrupts file should
               be consulted to decide whether the user is idle.  This  is  the
               default  if  xscreensaver  has  been compiled on a system which
               supports this mechanism (i.e., Linux systems.)

               The benefit to doing this is that xscreensaver  can  note  that
               the  user  is  active even when the X console is not the active
               one:  if  the  user  is  typing  in  another  virtual  console,
               xscreensaver  will  notice that and will fail to activate.  For
               example, if you're  playing  Quake  in  VGA-mode,  xscreensaver
               won't  wake  up  in the middle of your game and start competing
               for CPU.

               The drawback to doing this is that perhaps you really  do  want
               idleness  on the X console to cause the X display to lock, even
               if there is activity on other virtual consoles.   If  you  want
               that,  then  set  this  option  to  False.  (Or just lock the X
               console manually.)

               The default value for this resource is True, on  systems  where
               it works.

       overlayStderr (class Boolean)
               If  captureStderr is True, and your server supports ``overlay''
               visuals, then the text will be written into one of  the  higher
               layers   instead   of  into  the  same  layer  as  the  running
               screenhack.  Set this to False  to  disable  that  (though  you
               shouldn't need to.)

       overlayTextForeground (class Foreground)
               The  foreground  color  used  for  the  stdout/stderr  text, if
               captureStderr is true.  Default: Yellow.

       overlayTextBackground (class Background)
               The background  color  used  for  the  stdout/stderr  text,  if
               captureStderr is true.  Default: Black.

       bourneShell (class BourneShell)
               The  pathname  of  the  shell  that  xscreensaver uses to start
               subprocesses.  This must be  whatever  your  local  variant  of
               /bin/sh is: in particular, it must not be csh.

ENVIRONMENT

       DISPLAY to  get  the default host and display number, and to inform the
               sub-programs of the screen on which to draw.

       XSCREENSAVER_WINDOW
               Passed to sub-programs to indicate the  ID  of  the  window  on
               which they should draw on.  This is necessary on Xinerama/RANDR
               systems where multiple physical monitors  share  a  single  X11
               "Screen".

       PATH    to find the sub-programs to run.

       HOME    for the directory in which to read the .xscreensaver file.

       XENVIRONMENT
               to  get  the  name of a resource file that overrides the global
               resources stored in the RESOURCE_MANAGER property.

UPGRADES

       The latest version of xscreensaver, an online version of  this  manual,
       and a FAQ can always be found at http://www.jwz.org/xscreensaver/

SEE ALSO

       X(1),     Xsecurity(1),    xauth(1),    xdm(1),    gdm(1),    xhost(1),
       xscreensaver-demo(1),                          xscreensaver-command(1),
       xscreensaver-gl-helper(1),                    xscreensaver-getimage(1),
       xscreensaver-text(1).

COPYRIGHT

       Copyright (C) 1991-2011 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>.  Written in late 1991; version 1.0 posted
       to comp.sources.x on 17-Aug-1992.

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

       And a huge thank you to the hundreds of people who have contributed, in
       large  ways and small, to the xscreensaver collection over the past two
       decades!