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NAME

       xscreensaver - extensible screen saver and screen locking framework

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  parameter  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  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

           2: Launch xscreensaver at login.
              Open "Startup Applications" and add "xscreensaver".

           3: Make "Lock Screen" use xscreensaver.
              sudo ln -sf /usr/bin/xscreensaver-command \
                          /usr/bin/gnome-screensaver-command

USING KDE

       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".

           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.
              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", 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:

              #!/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 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).

BUGS

       Bugs?  There are no bugs.  Ok, well, maybe.  If you  find  one,  please
       let me know.  http://www.jwz.org/xscreensaver/bugs.php 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
           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)  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.

       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.

       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) or kdmctl(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.

       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                          
\
                      ico -r -faces -sleep 1 -obj ico    
\
                      xdaliclock -builtin2 -root         
\
                      xv -root -rmode 5 image.gif -quit  

               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.)

               Visuals:

               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        
\
                      color:  color-program -root        
\
               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   
\
                      TrueColor:   24bit-program -root   
\
               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.  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  ©  1991-2013  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!



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