Provided by: xscreensaver_5.45+dfsg1-2ubuntu1_amd64 bug


       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-saving 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 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.


       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

       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  parameter  in the .xscreensaver file, you would write the
       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.)


       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.

               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 xscreensaver window itself.
               If xscreensaver is crashing, you might need to do this in order to see  the  error

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


       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).


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

       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.


       For  the  better  part  of a decade, GNOME shipped xscreensaver as-is, and everything just
       worked out of the box.  In 2005, however, they decided to re-invent  the  wheel  and  ship
       their  own replacement for the xscreensaver daemon called "gnome-screensaver", rather than
       improving xscreensaver and contributing their changes back.   As  a  result,  the  "gnome-
       screensaver"  program  is insecure, bug-ridden, and missing many features of xscreensaver.
       You shouldn't use it.

       To replace gnome-screensaver with xscreensaver:

           1: Fully uninstall the gnome-screensaver package.
              sudo apt-get remove gnome-screensaver
              or possibly
              sudo dpkg -P gnome-screensaver
              Be careful that it doesn't try to uninstall all of GNOME.

           2: Launch xscreensaver at login.

              Select "Startup Applications" from the menu  (or  manually  launch  "gnome-session-
              properties") and add "xscreensaver".

              Do  this as your normal user account, not as root.  (This should go without saying,
              because you should never, ever, ever be logged in to the graphical desktop as  user

           3: Make GNOME's "Lock Screen" use xscreensaver.
              sudo ln -sf /usr/bin/xscreensaver-command \
              That  doesn't  work under Unity, though.  Apparently it has its own built-in screen
              locker which is not gnome-screensaver, and cannot be removed, and yet still manages
              to  be  bug-addled  and insecure.  Keep reinventing that wheel, guys!  (If you have
              figured out how to replace Unity's locking  "feature"  with  xscreensaver,  let  me

           4: Turn off Unity's built-in blanking.

              Open "System Settings / Brightness & Lock";
              Un-check "Start Automatically";
              Set "Turn screen off when inactive for" to "Never".
              Or possibly that has been randomly renamed again:
              Set "Settings / Power / Power Settings" to "Never".

           5: Log out and back in again.


       Like  GNOME,  KDE  also  decided  to  invent their own screen saver framework from scratch
       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".

              Or possibly: Open "System Settings" and select "Screen  Locking".   Un-check  "Lock
              Screen 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   something   like   ~/.kde/Autostart/   or

              If that doesn't work, then try this:

              Open   "System   Settings   /   Startup/Shutdown   /   Autostart",   and  then  add

              If you are lucky, that  will  create  a  "xscreensaver.desktop"  file  for  you  in
              ~/.config/autostart/ or ~/.kde/Autostart/.

           3: Make xscreensaver be an Autostart program.
              If  it  does  not  already  exist, create a file in your autostart directory called
              xscreensaver.desktop that contains the following six lines:
              [Desktop Entry]

           4: Make the various "lock session" buttons call xscreensaver.
              The file you want to replace next has moved around over  the  years.  It  might  be
              called  /usr/libexec/kde4/kscreenlocker,  or  it might be called "kdesktop_lock" or
              "krunner_lock" or "kscreenlocker_greet", and it might be in  /usr/lib/kde4/libexec/
              or  in /usr/kde/3.5/bin/ or even in /usr/bin/, depending on the distro and phase of
              the moon.  Replace the contents of that file with these two lines:
              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.


       If the above didn't do it, and your system has systemd(1), then give this a try:

       1: Create a service.
          Create the file ~/.config/systemd/user/xscreensaver.service containing:

       2. Enable it.
          systemctl --user enable xscreensaver
          Then restart X11.


       If  it's  still  not  working, but on your distro, that newfangled systemd(1) nonsense has
       already fallen out of favor?  Then maybe this will work: launch the "Startup Applications"
       applet, click "Add", enter these lines, then restart X11:
       Name: XScreenSaver
       Command: xscreensaver
       Comment: xscreensaver


       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).

       On the General page set the Local Greeter to Standard Greeter.

       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.)

       If that doesn't work, you can edit the config file directly. Edit /etc/X11/gdm/gdm.conf to
       BackgroundProgram=xscreensaver -nosplash
       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.

       It is safe to run xscreensaver as  root  (as  xdm  or  gdm  may  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).


       If you are running a system with systemd(1) 221 or newer, and if xscreensaver was compiled
       with libsystemd support, then closing the lid of your laptop will cause the screen to lock

       If not, then the screen might not lock until a few seconds  after  you  re-open  the  lid.
       Which  is less than ideal. So if you don't use systemd, you might want to get in the habit
       of doing xscreensaver-command -lock before closing the lid.


       Bugs?  There are no bugs.  Ok, well,  maybe.   If  you  find  one,  please  let  me  know.  explains  how to construct the most useful bug

       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

       XAUTH and XDM
           For  xscreensaver  to  work when launched by xdm(1) or gdm(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 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/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

           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  unprotected.  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 xorg.conf.

              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 xscreensaver to protect itself from that.  You  can  disable
              it globally with:
              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 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

               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  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

       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)
               This is an historical artifacts left over from  when  8-bit  displays  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  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

               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.  (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  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.

       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 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.

       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  suppressed.  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

       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.

                       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

       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

               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.)


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

                    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

       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.


       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 "Screen".

       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


       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),


       Copyright © 1991-2020 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.


       Jamie  Zawinski <>.  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!