xscreensaver - extensible screen saver framework, plus locking
xscreensaver [-display host:display.screen] [-verbose] [-no-capture-stderr] [-no-splash]
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:
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: unlike xlock(1), 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) pro-
gram, and change the settings through the GUI. The rest of this manual page describes
lower level ways of changing settings.
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 over-
rides any settings in the resource database.
The syntax of the .xscreensaver file is similar to that of the .Xdefaults file; for exam-
ple, to set the timeout paramter in the .xscreensaver file, you would write the following:
whereas, in the .Xdefaults file, you would write
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 tell
the running xscreensaver process to re-initialize itself, like so:
Note that if you changed the .Xdefaults file, you might also need to run xrdb(1):
xrdb < ~/.Xdefaults
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.)
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 run-
ning 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
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 dia-
log 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 dis-
play hardware support power management; not all do. See the Power Management sec-
tion, below, for more information.
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
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, Pseu-
doColor, 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 con-
trol 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)
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
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.
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 Netscape if it is already running, otherwise, will
launch a new Netscape 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.
prefsCommand (class PrefsCommand)
This is the shell command run when the Prefs button on the splash window is
pressed. It defaults to xscreensaver-demo -prefs.
nice (class Nice)
The sub-processes created by xscreensaver will be ``niced'' to this level, so that
they are given lower priority than other processes on the system, and don't
increase the load unnecessarily. The default is 10.
(Higher numbers mean lower priority; see nice(1) for details.)
memoryLimit (class MemoryLimit)
The sub-processes created by xscreensaver will not be allowed to allocate more
than this much memory (more accurately, this is the maximum size their address
space may become.) If any sub-process tries to allocate more than this, malloc(3)
will fail, and the process will likely exit (or safely crash) rather than going
forth and hogging memory.
The assumption here is that if one of the screenhacks is trying to use a lot of
memory, then something has gone wrong, and it's better to kill that program than
to overload the machine.
Default: 0, meaning "no limit." 30M is a good choice on most systems. (But
beware that setting this to a small value can cause OpenGL programs to malfunction
on certain systems.)
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 cer-
tain 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.
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 screen-
saver 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.
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.
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 xscreen-
saver-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 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 at random, 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
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
If the display has multiple screens, then a different program will be run for each
screen. (All screens are blanked and unblanked simultaniously.)
Note that you must escape the newlines; here is an example of how you might set
this in your ~/.xscreensaver file:
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.)
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 col-
ormap 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 appropri-
ate 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.
Normally you won't 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.
windowCreationTimeout (class Time)
When server extensions are not in use, this controls the delay between when win-
dows are created and when xscreensaver selects events on them. Default 30 sec-
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 xscreen-
saver 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...)
sgiSaverExtension (class Boolean)
There are a number of different X server extensions which can make xscreensaver's
job easier. The next few resources specify whether these extensions should be
utilized if they are available.
This resource controls whether the SGI SCREEN_SAVER server extension will be used
to decide whether the user is idle. This is the default if xscreensaver has been
compiled with support for this extension (which is the default on SGI systems.).
If it is available, the SCREEN_SAVER method is faster and more reliable than what
will be done otherwise, so use it if you can. (This extension is only available
on Silicon Graphics systems, unfortunately.)
mitSaverExtension (class Boolean)
This resource controls whether the MIT-SCREEN-SAVER server extension will be used
to decide whether the user is idle. However, the default for this resource is
false, because even if this extension is available, it is flaky (and it also makes
the fade option not work properly.) Use of this extension is not recommended.
xidleExtension (class Boolean)
This resource controls whether the XIDLE server extension will be used to decide
whether the user is idle. This is the default if xscreensaver has been compiled
with support for this extension. (This extension is only available for X11R4 and
X11R5 systems, unfortunately.)
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
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.
overlayTextBackground (class Background)
The background color used for the stdout/stderr text, if captureStderr is true.
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.
xscreensaver also accepts a few command-line options, mostly for use when debugging: for
normal operation, you should configure things via the ~/.xscreensaver file.
The X display to use. For displays with multiple screens, XScreenSaver will man-
age all screens on the display simultaniously.
Same as setting the verbose resource to true: print diagnostics on stderr and on
the xscreensaver window.
Same as setting the captureStderr resource to false: do not redirect the stdout
and stderr streams to the xscreensaver window itself. If xscreensaver is crash-
ing, you might need to do this in order to see the error message.
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.
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.
Before launching a subprocess, xscreensaver stores an appropriate value for $DISPLAY in
the environment that the child will receive. (This is so that if you start xscreensaver
with a -display argument, the programs which xscreensaver launches will draw on the same
display; and so that the child will end up drawing on the appropriate screen of a multi-
When the screensaver turns off, or is killed, care is taken to restore the ``real'' vir-
tual root window if there is one. Because of this, it is important that you not kill the
screensaver process with kill -9 if you are running a virtual-root window manager. If you
kill it with -9, you may need to restart your window manager to repair the damage. This
isn't an issue if you aren't running a virtual-root window manager.
For all the gory details, see the commentary at the top of xscreensaver.c.
You can control a running screensaver process by using the xscreensaver-command(1) program
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.
As of version 3.28, the ~/.xscreensaver file controls the configuration of your display's
power management settings: if you have used xset(1) to change your power management set-
tings, 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
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.
You can run xscreensaver from your xdm(1) session, so that the screensaver will run even
when nobody is logged in on the console.
The trick to using xscreensaver with xdm is this: keep in mind the two very different
states in which xscreensaver will be running:
1: Nobody logged in.
If you're thinking of running xscreensaver from XDM at all, then it's probably
because you want graphics demos to be running on the console when nobody is logged
in there. In this case, xscreensaver will function only as a screen saver, not a
screen locker: it doesn't make sense for xscreensaver to lock the screen, since
nobody is logged in yet! The only thing on the screen is the XDM login prompt.
2: Somebody logged in.
Once someone has logged in through the XDM login window, the situation is very dif-
ferent. For example: now it makes sense to lock the screen (and prompt for the
logged in user's password); and now xscreensaver should consult that user's
~/.xscreensaver file; and so on.
The difference between these two states comes down to a question of, which user is the
xscreensaver process running as? For the first state, it doesn't matter. If you start
xscreensaver in the usual XDM way, then xscreensaver will probably end up running as root,
which is fine for the first case (the ``nobody logged in'' case.)
However, once someone is logged in, running as root is no longer fine: because xscreen-
saver will be consulting root's .xscreensaver file instead of that of the logged in user,
and won't be prompting for the logged in user's password, and so on. (This is not a secu-
rity problem, it's just not what you want.)
So, once someone has logged in, you want xscreensaver to be running as that user. The way
to accomplish this is to kill the old xscreensaver process and start a new one (as the new
The simplest way to accomplish all of this is as follows:
1: Launch xscreensaver before anyone logs in.
To the file /usr/lib/X11/xdm/Xsetup, add the lines
This will run xscreensaver as root, over the XDM login window. Moving the mouse
will cause the screen to un-blank, and allow the user to type their password at XDM
to log in.
2: Restart xscreensaver when someone logs in.
Near the top of the file /usr/lib/X11/xdm/Xsession, add those same lines:
When someone logs in, this will kill off the existing (root) xscreensaver process,
and start a new one, running as the user who has just logged in. If the user's
.xscreensaver file requests locking, they'll get it. They will also get their own
choice of timeouts, and graphics demos, and so on.
Alternately, each user could just put those lines in their personal ~/.xsession
Make sure you have $PATH set up correctly in the Xsetup and Xsession scripts, or xdm won't
be able to find xscreensaver, and/or xscreensaver won't be able to find its graphics
(If your system does not seem to be executing the Xsetup file, you may need to configure
it to do so: the traditional way to do this is to make that file the value of the Display-
Manager*setup resource in the /usr/lib/X11/xdm/xdm-config file. See the man page for
xdm(1) for more details.)
It is safe to run xscreensaver as root (as xdm is likely to do.) If run as root, xscreen-
saver 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 xdm, then this prob-
ably means that you have xauth(1) or some other security mechanism turned on. One way
around this is to add "xhost +localhost" to Xsetup, just before xscreensaver is launched.
Note that this will give access to the X server to anyone capable of logging in to the
local machine, so in some environments, this might not be appropriate. If turning off
file-system-based access control is not acceptable, then running xscreensaver from the
Xsetup file might not be possible, and xscreensaver will only work when running as a nor-
mal, unprivileged user.
For more information on the X server's access control mechanisms, see the man pages for
X(1), Xsecurity(1), xauth(1), and xhost(1).
Using xscreensaver with gdm(1) is easy, because gdm has a configuration tool. Just fire
up gdmconfig(1) and on the Background page, type "xscreensaver -nosplash" into the Back-
ground 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 start-
ing xscreensaver on their own, if they want.)
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.
USING CDE (COMMON DESKTOP ENVIRONMENT)
The easiest way to use xscreensaver on a system with CDE is to simply switch off the
built-in CDE screensaver, and use xscreensaver instead; and second, to tell the front
panel to run xscreensaver-command(1) with the -lock option when the Lock icon is clicked.
To accomplish this involves five steps:
1: Switch off CDE's locker
Do this by turning off ``Screen Saver and Screen Lock'' in the Screen section of
the Style Manager.
2: Edit sessionetc
Edit the file ~/.dt/sessions/sessionetc and add to it the line
And make sure the sessionetc file is executable. This will cause xscreensaver to
be launched when you log in. (As always, make sure that xscreensaver and the
graphics demos are on your $PATH; the path needs to be set in .cshrc and/or .dtpro-
file, not .login.)
3: Create XScreenSaver.dt
Create a file called ~/.dt/types/XScreenSaver.dt with the following contents:
EXEC_STRING xscreensaver-command -lock
This defines a ``lock'' command for the CDE front panel, that knows how to talk to
4: Create Lock.fp
Create a file called ~/.dt/types/Lock.fp with the following contents:
This associates the CDE front panel ``Lock'' icon with the lock command we just
defined in step 3.
Select ``Restart Workspace Manager'' from the popup menu to make your changes take
effect. If things seem not to be working, check the file ~/.dt/errorlog for error
USING HP VUE (VISUAL USER ENVIRONMENT)
Since CDE is a descendant of VUE, the instructions for using xscreensaver under VUE are
similar to the above:
1: Switch off VUE's locker
Open the ``Style Manager'' and select ``Screen.'' Turn off ``Screen Saver and
Screen Lock'' option.
2: Make sure you have a Session
Next, go to the Style Manager's, ``Startup'' page. Click on ``Set Home Session''
to create a session, then on ``Return to Home Session'' to select this session each
time you log in.
3: Edit vue.session
Edit the file ~/.vue/sessions/home/vue.session and add to it the line
vuesmcmd -screen 0 -cmd "xscreensaver"
This will cause xscreensaver to be launched when you log in. (As always, make sure
that xscreensaver and the graphics demos are on your $PATH; the path needs to be
set in .cshrc and/or .profile, not .login.)
3: Edit vuewmrc
Edit the file ~/.vue/vuewmrc and add (or change) the Lock control:
PUSH_ACTION f.exec "xscreensaver-command -lock"
This associates the VUE front panel ``Lock'' icon with the xscreensaver lock com-
USING KDE (K DESKTOP ENVIRONMENT)
I understand that KDE has invented their own wrapper around xscreensaver, that is inferior
to xscreensaver-demo(1) in any number of ways. I've never actually seen it, but I'm told
that this is the way you disable it:
1: Switch off KDE's screen saver.
Open the ``Control Center'' and select the ``Look and Feel / Screensaver'' page.
Turn off the ``Enable Screensaver'' checkbox.
2: Find your Autostart directory.
Open the ``Look and Feel / Desktop / Paths'' page, and see what your ``Autostart''
directory is set to: it will probably be ~/.kde3/Autostart/ or something similar.
3: Make xscreensaver be an Autostart program.
Create a file in your autostart directory called xscreensaver.desktop that contains
the following five lines:
Now use xscreensaver normally, controlling it via the usual xscreensaver-demo(1) and
ADDING TO MENUS
The xscreensaver-command(1) program is a perfect candidate for something to add to your
window manager's popup menus. If you use mwm(1), 4Dwm(1), twm(1), or (probably) any of
twm's many descendants, you can do it like this:
1. Create ~/.mwmrc (or ~/.twmrc or ...)
If you don't have a ~/.mwmrc file (or, on SGIs, a ~/.4Dwmrc file; or, with twm, a
~/.twmrc file) then create one by making a copy of the /usr/lib/X11/system.mwmrc file
(or /usr/lib/X11/twm/system.twmrc, and so on.)
2. Add a menu definition.
Something like this:
"Blank Screen Now" !"sleep 3; xscreensaver-command -activate"
"Lock Screen Now" !"sleep 3; xscreensaver-command -lock"
"Screen Saver Demo" !"xscreensaver-demo"
"Screen Saver Preferences" !"xscreensaver-demo -prefs"
"Reinitialize Screen Saver" !"xscreensaver-command -restart"
"Kill Screen Saver" !"xscreensaver-command -exit"
"Launch Screen Saver" !"xscreensaver &"
3. Add the menu
For mwm(1) and 4Dwm(1), find the section of the file that says Menu DefaultRootMenu.
For twm(1), it will probably be menu "defops". If you add a line somewhere in that
menu definition that reads
"XScreenSaver" f.menu XScreenSaver
then this will add an XScreenSaver sub-menu to your default root-window popup menu.
Alternately, you could just put the xscreensaver menu items directly into the root
For Fvwm2, the process is similar: first create a ~/.fvwm2rc file if you don't already
have one, by making a copy of the /etc/X11/fvwm2/system.fvwm2rc file. Then, add a menu
definition to it:
AddToMenu XScreenSaver "XScreenSaver" Title
+ "Blank Screen Now" Exec xscreensaver-command -activate
+ "Lock Screen Now" Exec xscreensaver-command -lock
+ "Screen Saver Demo" Exec xscreensaver-command -demo
+ "Screen Saver Preferences" Exec xscreensaver-command -prefs
+ "Reinitialize Screen Saver" Exec xscreensaver-command -restart
+ "Kill Screen Saver" Exec xscreensaver-command -exit
+ "Launch Screen Saver" Exec xscreensaver
+ "Run Next Demo" Exec xscreensaver-command -next
+ "Run Previous Demo" Exec xscreensaver-command -prev
# To put the XScreenSaver sub-menu at the end of the root menu:
AddToMenu RootMenu "XScreenSaver" Popup XScreenSaver
The Enlightenment window manager keeps each of its menus in a separate file. So, you need
to create a file named ~/.enlightenment/xscreensaver.menu with the contents:
"Blank Screen Now" NULL exec "xscreensaver-command -activate"
"Lock Screen Now" NULL exec "xscreensaver-command -lock"
"Screen Saver Demo" NULL exec "xscreensaver-command -demo"
"Screen Saver Prefs" NULL exec "xscreensaver-command -prefs"
"Reinitialize Saver" NULL exec "xscreensaver-command -restart"
"Kill Screen Saver" NULL exec "xscreensaver-command -exit"
"Launch Screen Saver" NULL exec "xscreensaver"
"XScreenSaver" NULL menu "xscreensaver.menu"
to ~/.enlightenment/file.menu to put the XScreenSaver submenu on your left-button root-
As you see, every window manager does this stuff gratuitously differently, just to make
your life difficult. You are in a maze of twisty menu configuration languages, all alike.
Bugs? There are no bugs. Ok, well, maybe. If you find one, please let me know.
http://www.jwz.org/xscreensaver/bugs.html explains how to construct the most useful bug
Locking and XDM
If xscreensaver has been launched from xdm(1) before anyone has logged in, you
will need to kill and then restart the xscreensaver daemon after you have logged
in, or you will be confused by the results. (For example, locking won't work, and
your ~/.xscreensaver file will be ignored.)
When you are logged in, you want the xscreensaver daemon to be running under your
user id, not as root or some other user.
If it has already been started by xdm, you can kill it by sending it the exit com-
mand, and then re-launching it as you, by putting something like the following in
your personal X startup script:
The ``Using XDM(1)'' section, above, goes into more detail, and explains how to
configure the system to do this for all users automatically.
Locking and root logins
In order for it to be safe for xscreensaver to be launched by xdm, certain precau-
tions had to be taken, among them that xscreensaver never runs as root. In par-
ticular, 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), programs running on the local
machine as user "nobody" must be able to connect to the X server. This means that
if you want to run xscreensaver on the console while nobody is logged in, you may
need to disable cookie-based access control (and allow all users who can log in to
the local machine to connect to the display.)
You should be sure that this is an acceptable thing to do in your environment
before doing it. See the ``Using XDM(1)'' section, above, for more details.
If anyone has suggestions on how xscreensaver could be made to work with xdm(1)
without first turning off .Xauthority-based access control, please let me know.
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 rou-
tine 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 con-
figure 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. So,
after you change your password, you'll have to do
to make xscreensaver notice.
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 creat-
ing 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!
Colormap lossage: TWM
The installColormap option doesn't work very well with the twm(1) window manager
and its descendants.
There is a race condition between the screensaver and this window manager, which
can result in the screensaver's colormap not getting installed properly, meaning
the graphics hacks will appear in essentially random colors. (If the screen goes
white instead of black, this is probably why.)
The mwm(1) and olwm(1) window managers don't have this problem. The race condi-
tion exists because X (really, ICCCM) does not provide a way for an OverrideRedi-
rect window to have its own colormap, short of grabbing the server (which is nei-
ther a good idea, nor really possible with the current design.) What happens is
that, as soon as xscreensaver installs its colormap, twm responds to the resultant
ColormapNotify event by re-instaling the default colormap. Apparently, twm
doesn't always do this; it seems to do it regularly if the screensaver is acti-
vated from a menu item, but seems to not do it if the screensaver comes on of its
own volition, or is activated from another console.
Attention, window manager authors!
You should only call XInstallColormap(3) in response to user events. That is,
it is appropriate to install a colormap in response to FocusIn, FocusOut,
EnterNotify, and LeaveNotify events; but it is not appropriate to call it in
response to ColormapNotify events. If you install colormaps in response to
application actions as well as in response to user actions, then you create
the situation where it is impossible for override-redirect applications (such
as xscreensaver) to display their windows in the proper colors.
Colormap lossage: XV, XAnim, XEarth
Some programs don't operate properly on visuals other than the default one, or
with colormaps other than the default one. See the discussion of the magic
"default-n" visual name in the description of the programs resource in the Config-
uration section. When programs only work with the default colormap, you need to
use a syntax like this:
default-n: xv -root image-1.gif -quit \n\
default-n: xearth -nostars -wait 0 \n\
It would also work to turn off the installColormap option altogether, but that
would deny extra colors to those programs that can take advantage of them.
Although this program ``nices'' the subprocesses that it starts, graphics-inten-
sive subprograms can still overload the machine by causing the X server process
itself (which is not ``niced'') to suck a lot of cycles. Care should be taken to
slow down programs intended for use as screensavers by inserting strategic calls
to sleep(3) or usleep(3) (or making liberal use of any -delay options which the
programs may provide.)
Note that the OpenGL-based graphics demos are real pigs on machines that don't
have texture hardware.
Also, an active screensaver will cause your X server to be pretty much permanently
swapped in; but the same is true of any program that draws periodically, like
xclock(1) or xload(1).
Latency and Responsiveness
If the subprocess is drawing too quickly and the connection to the X server is a
slow one (such as an X terminal running over a phone line) then the screensaver
might not turn off right away when the user becomes active again (the ico(1) demo
has this problem if being run in full-speed mode). This can be alleviated by
inserting strategic calls to XSync(3) in code intended for use as a screensaver.
This prevents too much graphics activity from being buffered up.
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 interpreta-
tion 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
Some Linux systems come with a VT_LOCKSWITCH ioctl, that one could theoretically
use to prevent VT-switching while the screen is locked; but unfortunately, this
ioctl can only be used by root, which means that xscreensaver can't use it (since
xscreensaver disavows its privileges shortly after startup, for security reasons.)
Any suggestions for other solutions to this problem are welcome.
Apparently there are some problems with XView programs getting confused and think-
ing that the screensaver window is the real root window even when the screensaver
is not active: ClientMessages intended for the window manager are sent to the
screensaver window instead. This could be solved by making xscreensaver forward
all unrecognised ClientMessages to the real root window, but there may be other
problems as well. If anyone has any insight on the cause of this problem, please
let me know. (XView is an X11 toolkit that implements the (quite abominable) Sun
MIT Extension and Fading
The MIT-SCREEN-SAVER extension is junk. Don't use it.
When using the MIT-SCREEN-SAVER extension in conjunction with the fade option,
you'll notice an unattractive flicker just before the fade begins. This is
because the server maps a black window just before it tells the xscreensaver
process to activate. The xscreensaver process immediately unmaps that window, but
this results in a flicker. I haven't figured a way to get around this; it seems
to be a fundamental property of the (mis-) design of this server extension.
It sure would be nice if someone would implement the SGI SCREEN_SAVER extension in
XFree86; it's dead simple, and works far better than the overengineered and broken
SGI Power Saver
If you're running Irix 6.3, you might find that your monitor is powering down
after an hour or two even if you've told it not to. This is fixed by SGI patches
2447 and 2537.
If you're running Irix 6.5, this bug is back. I don't know a fix.
MesaGL and Voodoo Cards
If you have a 3Dfx/Voodoo card, the default settings for xscreensaver will run the
GL-based graphics demos in such a way that they will not take advantage of the 3D
acceleration hardware. The solution is to change the programs entries for the GL
hacks from this:
gears -root \n\
MESA_GLX_FX=fullscreen gears \n\
That is, make sure that $MESA_GLX_FX is set to fullscreen, and don't tell the pro-
gram to draw on the root window. This may seem strange, but the setup used by
Mesa and these kinds of cards is strange!
For those who don't know, these cards work by sitting between your normal video
card and the monitor, and seizing control of the monitor when it's time to do 3D.
But this means that accelerated 3D only happens in full-screen mode (you can't do
it in a window, and you can't see the output of 3D and 2D programs simultan-
iously), and that 3D will probably drive your monitor at a lower resolution, as
well. It's bizarre.
This probably isn't ever necessary on more modern cards; I'm not sure.
If you find that GL programs only work properly when run as root, and not as nor-
mal users, then the problem is that your /dev/3dfx file is not configured prop-
erly. Check the Linux 3Dfx FAQ.
If procInterrupts is on (which is the default on Linux systems) and you're using
some program that toggles the state of your keyboard LEDs, xscreensaver won't work
right: turning those LEDs on or off causes a keyboard interrupt, which xscreen-
saver will interpret as user activity. So if you're using such a program, set the
procInterrupts resource to False.
If you are not making use of one of the server extensions (XIDLE, SGI
SCREEN_SAVER, or MIT-SCREEN-SAVER), then it is possible, in rare situations, for
xscreensaver to interfere with event propagation and make another X program mal-
function. For this to occur, that other application would need to not select Key-
Press events on its non-leaf windows within the first 30 seconds of their exis-
tence, but then select for them later. In this case, that client might fail to
receive those events. This isn't very likely, since programs generally select a
constant set of events immediately after creating their windows and then don't
change them, but this is the reason that it's a good idea to install and use one
of the server extensions instead, to work around this shortcoming in the X proto-
In all these years, I've not heard of even a single case of this happening, but it
is theoretically possible, so I'm mentioning it for completeness...
DISPLAY to get the default host and display number, and to inform the sub-programs of the
screen on which to draw.
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 http://www.jwz.org/xscreensaver/
X(1), xscreensaver-demo(1), xscreensaver-command(1), xscreensaver-gl-helper(1), xdm(1),
xset(1), Xsecurity(1), xauth(1), xhost(1). ant(1), atlantis(1), attraction(1), blit-
spin(1), bouboule(1), braid(1), bsod(1), bubble3d(1), bubbles(1), cage(1), compass(1),
coral(1), critical(1), crystal(1), cynosure(1), decayscreen(1), deco(1), deluxe(1),
demon(1), discrete(1), distort(1), drift(1), epicycle(1), fadeplot(1), flag(1), flame(1),
flow(1), forest(1), galaxy(1), gears(1), glplanet(1), goop(1), grav(1), greynetic(1),
halo(1), helix(1), hopalong(1), hypercube(1), ifs(1), imsmap(1), interference(1), jig-
saw(1), julia(1), kaleidescope(1), kumppa(1), lament(1), laser(1), lightning(1), lisa(1),
lissie(1), lmorph(1), loop(1), maze(1), moebius(1), moire(1), moire2(1), morph3d(1), moun-
tain(1), munch(1), noseguy(1), pedal(1), penetrate(1), penrose(1), petri(1), phosphor(1),
pipes(1), pulsar(1), pyro(1), qix(1), rd-bomb(1), rocks(1), rorschach(1), rotor(1),
rubik(1), sierpinski(1), slidescreen(1), slip(1), sonar(1), sphere(1), spiral(1), spot-
light(1), sproingies(1), squiral(1), stairs(1), starfish(1), strange(1), superquadrics(1),
swirl(1), t3d(1), triangle(1), truchet(1), vines(1), wander(1), worm(1), xflame(1),
xjack(1), xlyap(1), xmatrix(1), bongo(1), ico(1), xaos(1), xbouncebits(1), xcthugha(1),
xdaliclock(1), xfishtank(1), xmountains(1), xsplinefun(1), xswarm(1), xtacy(1), xv(1),
Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002 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 permis-
sion 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
Jamie Zawinski <email@example.com>. Written in late 1991; version 1.0 posted to comp.sources.x
Please let me know if you find any bugs or make any improvements.
Thanks to Angela Goodman for the XScreenSaver logo.
Thanks to the many people who have contributed graphics demos to the package.
Thanks to David Wojtowicz for implementing lockTimeout.
Thanks to Martin Kraemer for adding support for shadow passwords and locking-disabled
Thanks to Patrick Moreau for the VMS port.
Thanks to Mark Bowyer for figuring out how to hook it up to CDE.
Thanks to Nat Lanza for the Kerberos support.
Thanks to Bill Nottingham for the initial PAM support.
And thanks to Jon A. Christopher for implementing the Athena dialog support, back in the
days before Lesstif or Gtk were viable alternatives to Motif.
X Version 11 03-Feb-2003 (4.07) XScreenSaver(1)