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man pages section 1: User Commands

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Updated: Wednesday, February 10, 2021

xscreensaver (1)


xscreensaver - extensible screen saver and screen locking framework


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


xscreensaver(1)               XScreenSaver manual              xscreensaver(1)

       xscreensaver - extensible screen saver and screen locking framework

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

       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-sav-
       ing features.

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

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

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

       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 .xscreen-
       saver 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  .Xde-
       faults file; for example, to set the timeout parameter in the .xscreen-
       saver 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
       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/share/X11/app-defaults/XScreenSaver, but differ-
       ent systems might keep it in a different place.

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

       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  simultan-

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

               Do not redirect the stdout and stderr streams to  the  xscreen-
               saver  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

       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 screen-
       saver  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  xscreen-
       saver-command(1) program (which see).

       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

       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.  Alternatively,
       you can edit the ~/.xscreensaver file directly.

       If  the  power  management  section  is  grayed  out  in  the  xscreen-
       saver-demo(1) window,  then that means that your X server does not sup-
       port 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 set-
       tings 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.

       By default, GNOME 3 uses the gdm(8) screen shield to blank and lock the
       screen, and does not run xscreensaver or offer any screensaver modes.

       To run xscreensaver as part of your GNOME 3 session,  symlink  or  copy
       the  file  /usr/lib/xscreensaver/xscreensaver-autostart.desktop to your
       ~/.config/autostart/ directory.

       To prevent GNOME screen shield from locking the display, run:
          gsettings set org.gnome.desktop.screensaver lock-enabled false

       To prevent gnome-shell from dimming and turning off the display, run:
          gsettings set org.gnome.desktop.session idle-delay 0

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

       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  con-
           sole, 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 some-

           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)  or  gdm(1),  pro-
           grams 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 GDM"  section,  above,
           for more details.

           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/xscreen-
           saver 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  con-
           sume  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.)

       Magic Backdoor Keystrokes
           The  XFree86  X server and the Linux kernel both trap certain magic
           keystrokes before X11 client programs ever see them.  If  you  care
           about keeping your screen locked, this is a big problem.

              This  keystroke  kills the X server, and on some systems, leaves
              you at a text console.  If the user launched X11 manually,  that
              text console will still be logged in.  To disable this keystroke
              globally and permanently, you need to set the  DontZap  flag  in
              your  xorg.conf  or  XF86Config  or XF86Config-4 file, depending
              which is in use on your system.  See XF86Config(5) for details.

           Ctrl-Alt-F1, Ctrl-Alt-F2, etc.
              These keystrokes will switch to  a  different  virtual  console,
              while leaving the console that X11 is running on locked.  If you
              left a shell logged in on another virtual console, it is  unpro-
              tected.   So  don't  leave yourself logged in on other consoles.
              You can disable VT switching globally and permanently by setting
              DontVTSwitch  in your xorg.conf, but that might make your system
              harder to use, since VT switching is an actual useful feature.

              There is no way to disable VT switching only when the screen  is
              locked.  It's all or nothing.

              This  keystroke  kills  any X11 app that holds a lock, so typing
              this will kill xscreensaver and unlock  the  screen.   This  so-
              called  "feature"  showed  up in the X server in 2008, and as of
              2011, some vendors are shipping it turned on  by  default.   How
              nice.   You can disable it by turning off AllowClosedownGrabs in

              This is the Linux kernel "OOM-killer" keystroke.  It shoots down
              random long-running programs of its choosing, and so might might
              target and kill xscreensaver, and there's no  way  for  xscreen-
              saver  to protect itself from that.  You can disable it globally
              echo 176 > /proc/sys/kernel/sysrq
       There's little that I can do to make the screen  locker  be  secure  so
       long  as  the  kernel  and  X11 developers are actively working against
       security like this.  The strength  of  the  lock  on  your  front  door
       doesn't  matter  much  so  long as someone else in the house insists on
       leaving a key under the welcome mat.

       Dangerous Backdoor Server Extensions
           Many distros enable by default several X11 server  extensions  that
           can  be  used  to  bypass grabs, and thus snoop on you while you're
           typing your password.  These extensions are nominally for debugging
           and  automation, but they are also security-circumventing keystroke
           loggers.  If your server is configured to load the RECORD, XTRAP or
           XTEST  extensions, you absolutely should disable those, 100% of the
           time.  Look for them in xorg.conf or whatever it is called.

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

       timeout (class Time)
               The screensaver will activate (blank the screen) after the key-
               board  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.

               The  running  saver  will be restarted every cycle minutes even
               when mode is one, since some  savers  tend  to  converge  on  a
               steady state.

       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  activa-
               tion)  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 pow-
               ers  down  completely.   Note  that these settings will have no
               effect unless both the X server and the display  hardware  sup-
               port  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 pow-
               ered down immediately upon blanking, regardless of other power-
               management settings.

       visualID (class VisualID)
               This is an historical artifacts left over from when 8-bit  dis-
               plays were still common.  You should probably ignore this.

               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  behav-
                       ior 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 mono-

               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, True-
                       Color, GrayScale, PseudoColor, or DirectColor.  Selects
                       the deepest visual of the given class.

               number  where  number (decimal or hex) is interpreted as a vis-
                       ual 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  shal-
                       lower 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  automati-
               cally.)   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.  (Which, in this century, you do.)

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

       timestamp (class Boolean)
               Whether to print the time of day along with any other  diagnos-
               tic 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

       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

       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/Net-
               scape 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  xscreen-
               saver-demo -prefs.

       newLoginCommand (class NewLoginCommand)
               If set, this is the shell command that is  run  when  the  "New
               Login"  button is pressed on the unlock dialog box, in order to
               create a new desktop session without logging out the  user  who
               has  locked the screen.  Typically this will be some variant of
               gdmflexiserver(1), kdmctl(1), lxdm(1) or dm-tool(1).

       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  unneces-
               sarily.   The default is 10.  (Higher numbers mean lower prior-
               ity; see nice(1) for details.)

       fade (class Boolean)
               If this is true, then when the screensaver activates, the  cur-
               rent  contents of the screen will fade to black instead of sim-
               ply 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 con-
               trolling terminal of the screensaver driver  process.   Default

       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.

       authWarningSlack (class Integer)
               If all failed unlock attempts (incorrect password entered) were
               made within this period of time, the usual  dialog  that  warns
               about  such  attempts  after  a  successful  login will be sup-
               pressed. The assumption is  that  incorrect  passwords  entered
               within  a  few  seconds of a correct one are user error, rather
               than hostile action.  Default 20 seconds.

       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

       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.

                       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 set-

               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

       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)  pro-

               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 sys-
               tem-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 dis-
               ables 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


               Because xscreensaver was created back when dinosaurs roamed the
               earth, it still contains support for some things you've  proba-
               bly  never  seen,  such as 1-bit monochrome monitors, grayscale
               monitors, and monitors capable of displaying  only  8-bit  col-
               ormapped images.

               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
                      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:

                    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 win-
                    dow: assumptions which xscreensaver can violate.

               If you specify a particular visual for a program, and that vis-
               ual 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 fre-
               quently 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, xscreen-
               saver 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  con-
               sole 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  screen-
               hack.   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  cap-
               tureStderr is true.  Default: Yellow.

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

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

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

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

       PATH    to find the sub-programs to run.

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

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

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

       See attributes(7) for descriptions of the following attributes:

       |Availability   | desktop/xscreensaver |
       |Stability      | Volatile             |
       X(7), Xsecurity(7), xauth(1), xdm(1), gdm(8),  gsettings(1),  xhost(1),
       xscreensaver-demo(1),         xscreensaver-command(1),         xscreen-
       saver-gl-helper(1), xscreensaver-getimage(1), xscreensaver-text(1).

       Copyright (C) 1991-2018 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  war-

       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

       This    software    was    built    from    source     available     at
       https://github.com/oracle/solaris-userland.    The  original  community
       source was downloaded  from   https://www.jwz.org/xscreensaver/xscreen-

       Further information about this software can be found on the open source
       community website at https://www.jwz.org/xscreensaver/.

X Version 11                  5.39 (12-Apr-2018)               xscreensaver(1)