Manual Pages for UNIX Operating System command usage for man xscreensaver
XScreenSaver manual xscreensaver(1)
NAME
xscreensaver - extensible screen saver framework, plus lock-
ing
SYNOPSIS
/usr/bin/xscreensaver [-display host:display.screen] [-ver-
bose] [-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 oth-
ers 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 the xscreensaver
program is a daemon that runs in the background; it is con-
trolled 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
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a .xscreensaver file in your home directory; or in the X
resource database. If the .xscreensaver file exists, it
overrides any settings in the resource database.
The syntax of the .xscreensaver file is similar to that of
the .Xdefaults file; for example, to set the timeout
paramter in the .xscreensaver file, you would write the fol-
lowing:
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/share/X11/app-defaults/XScreenSaver, but different sys-
tems might keep it in a different place.
When settings are changed in the Preferences dialog box (see
above) the current settings will be written to the .xscreen-
saver 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.
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-verbose
Same as setting the verbose resource to true: print
diagnostics on stderr and on the xscreensaver win-
dow.
-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 use-
ful 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.)
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To change your power management settings, run
xscreensaver-demo(1) and change the various timeouts through
the user interface. Alternately, you can edit the
~/.xscreensaver file directly.
If the power management section is grayed out in the
xscreensaver-demo(1) window, then that means that your X
server does not support the XDPMS extension, and so control
over the monitor's power state is not available.
If you're using a laptop, don't be surprised if changing the
DPMS settings has no effect: many laptops have monitor
power-saving behavior built in at a very low level that is
invisible to Unix and X. On such systems, you can typically
adjust the power-saving delays only by changing settings in
the BIOS in some hardware-specific way.
If DPMS seems not to be working with XFree86, make sure the
"DPMS" option is set in your /etc/X11/XF86Config file. See
the XF86Config(5) manual for details.
USING GNOME
For many years, GNOME shipped xscreensaver as-is, and every-
thing just worked out of the box. Recently, however,
they've been re-inventing the wheel again in the form of
"gnome-screensaver".
To replace gnome-screensaver with xscreensaver:
1: Turn off gnome-screensaver.
Open ``System / Preferences / Screensaver'' and
uncheck both boxes.
2: Stop gnome-screensaver from launching at login.
Run the command:
gconftool-2 --type boolean -s \
/apps/gnome_settings_daemon/screensaver/start_screensaver \
false
Or, just uninstall the "gnome-screensaver" package
entirely.
3: Launch xscreensaver at login.
Open ``System / Preferences / Sessions / Startup Pro-
grams''. Click ``Add'' and type ``xscreensaver''.
4: Tell Preferences to use the xscreensaver configurator.
Edit /usr/share/applications/gnome-screensaver-
preferences.desktop and change the Exec= line to say
Exec=xscreensaver-demo
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5: Make ``System / Quit / Lock Screen'' use xscreensaver.
Run the command:
sudo ln -sf /usr/bin/xscreensaver-command \
/usr/bin/gnome-screensaver-command
USING KDE
KDE also has invented their own screen saver framework
instead of simply using xscreensaver. To replace the KDE
screen saver with xscreensaver, do the following:
1: Turn off KDE's screen saver.
Open the ``Control Center'' and select the ``Appear-
ance & 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 follow-
ing five lines:
[Desktop Entry]
Exec=xscreensaver
Name=XScreenSaver
Type=Application
X-KDE-StartupNotify=false
4: Make the various "lock session" buttons call xscreensaver.
Replace the file kdesktop_lock or krunner_lock or
kscreenlocker in /usr/bin/ (or possibly in
/usr/kde/3.5/bin/ or possibly in
/usr/lib/kde4/libexec/ or /usr/libexec/kde4/, depend-
ing on the distro and phase of the moon) with these
two lines:
#!/bin/sh
xscreensaver-command -lock
Make sure the file is executable (chmod a+x).
Now use xscreensaver normally, controlling it via the usual
xscreensaver-demo(1) and xscreensaver-command(1) mechanisms.
USING GDM
You can run xscreensaver from your gdm(1) session, so that
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the screensaver will run even when nobody is logged in on
the console. To do this, run gdmconfig(1) and on the Back-
ground page, type the command "xscreensaver -nosplash" into
the Background Program field. That will cause gdm to run
xscreensaver while nobody is logged in, and kill it as soon
as someone does log in. (The user will then be responsible
for starting xscreensaver on their own, if they want.)
Another way to accomplish the same thing is to edit the file
/etc/X11/gdm/gdm.conf to include:
BackgroundProgram=xscreensaver -nosplash
RunBackgroundProgramAlways=true
In this situation, the xscreensaver process will probably be
running as user gdm instead of root. You can configure the
settings for this nobody-logged-in state (timeouts, DPMS,
etc.) by editing the ~gdm/.xscreensaver file.
To get gdm to run the BackgroundProgram, you may need to
switch it from the "Graphical Greeter" to the "Standard
Greeter".
It is safe to run xscreensaver as root (as xdm is likely to
do.) If run as root, xscreensaver changes its effective
user and group ids to something safe (like "nobody") before
connecting to the X server or launching user-specified pro-
grams.
An unfortunate side effect of this (important) security pre-
caution is that it may conflict with cookie-based authenti-
cation.
If you get "connection refused" errors when running xscreen-
saver from gdm, then this probably means that you have
xauth(1) or some other security mechanism turned on. For
information on the X server's access control mechanisms, see
the man pages for X(1), Xsecurity(1), xauth(1), and
xhost(1).
BUGS
Bugs? There are no bugs. Ok, well, maybe. If you find
one, please let me know.
http://www.jwz.org/xscreensaver/bugs.html explains how to
construct the most useful bug reports.
Locking and XDM
If xscreensaver has been launched from xdm(1) before
anyone has logged in, you will need to kill and then
restart the xscreensaver daemon after you have
logged in, or you will be confused by the results.
(For example, locking won't work, and your
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~/.xscreensaver file will be ignored.)
When you are logged in, you want the xscreensaver
daemon to be running under your user id, not as root
or some other user.
If it has already been started by xdm, you can kill
it by sending it the exit command, and then re-
launching it as you, by putting something like the
following in your personal X startup script:
xscreensaver-command -exit
xscreensaver &
The ``Using XDM(1)'' section, above, goes into more
detail, and explains how to configure the system to
do this for all users automatically.
Locking and root logins
In order for it to be safe for xscreensaver to be
launched by xdm, certain precautions had to be
taken, among them that xscreensaver never runs as
root. In particular, if it is launched as root (as
xdm is likely to do), xscreensaver will disavow its
privileges, and switch itself to a safe user id
(such as nobody.)
An implication of this is that if you log in as root
on the console, xscreensaver will refuse to lock the
screen (because it can't tell the difference between
root being logged in on the console, and a normal
user being logged in on the console but xscreensaver
having been launched by the xdm(1) Xsetup file.)
The solution to this is simple: you shouldn't be
logging in on the console as root in the first
place! (What, are you crazy or something?)
Proper Unix hygiene dictates that you should log in
as yourself, and su(1) to root as necessary. People
who spend their day logged in as root are just beg-
ging for disaster.
XAUTH and XDM
For xscreensaver to work when launched by xdm(1),
programs running on the local machine as user
"nobody" must be able to connect to the X server.
This means that if you want to run xscreensaver on
the console while nobody is logged in, you may need
to disable cookie-based access control (and allow
all users who can log in to the local machine to
connect to the display.)
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You should be sure that this is an acceptable thing
to do in your environment before doing it. See the
``Using XDM(1)'' section, above, for more details.
Passwords
If you get an error message at startup like
``couldn't get password of user'' then this probably
means that you're on a system in which the
getpwent(3) library routine can only be effectively
used by root. If this is the case, then xscreen-
saver 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 pass-
words 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 pass-
word to unlock the screen until xscreensaver is res-
tarted. 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 respond-
ing, ``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 prob-
lem in advance, so if you have PAM, make sure it is
configured correctly!
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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 vir-
tual 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
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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 xscreen-
saver), 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 pass-
word 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
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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.
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 pro-
grams. (OpenGL programs have somewhat dif-
ferent requirements than other X programs.)
class where class is one of StaticGray, Sta-
ticColor, 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 shal-
lower one than would otherwise have been
chosen.
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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 possi-
ble. This is the default. (This only applies when
the screen's default visual is being used, since
non-default visuals get their own colormaps automat-
ically.) 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, oth-
erwise, 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)
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This is the shell command run when the Prefs button
on the splash window is pressed. It defaults to
xscreensaver-demo -prefs.
nice (class Nice)
The sub-processes created by xscreensaver will be
``niced'' to this level, so that they are given
lower priority than other processes on the system,
and don't increase the load unnecessarily. The
default is 10.
(Higher numbers mean lower priority; see nice(1) for
details.)
fade (class Boolean)
If this is true, then when the screensaver
activates, the current contents of the screen will
fade to black instead of simply winking out. This
only works on certain systems. A fade will also be
done when switching graphics hacks (when the cycle
timer expires.) Default: true.
unfade (class Boolean)
If this is true, then when the screensaver deac-
tivates, 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 xscreen-
saver 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)
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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 pro-
grams 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 long-
standing XFree86 bug #421. See the xscreensaver FAQ
for details.
font (class Font)
The font used for the stdout/stderr text, if cap-
tureStderr 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 ran-
dom 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!
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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 semi-
colons, 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 particu-
lar 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. How-
ever, if the user disables it, then their setting
takes precedence.
If the display has multiple screens, then a dif-
ferent program will be run for each screen. (All
screens are blanked and unblanked simultaneously.)
Note that you must escape the newlines; here is an
example of how you might set this in your
~/.xscreensaver file:
programs: \
qix -root \n\
ico -r -faces -sleep 1 -obj ico \n\
xdaliclock -builtin2 -root \n\
xv -root -rmode 5 image.gif -quit \n
Make sure your $PATH environment variable is set up
correctly before xscreensaver is launched, or it
won't be able to find the programs listed in the
programs resource.
To use a program as a screensaver, two things are
required: that that program draw on the root window
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(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 pro-
gram 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 accommo-
dated:
PseudoColor: cmap-program -root \n\
TrueColor: 24bit-program -root \n\
In addition to the symbolic visual names described
above (in the discussion of the visualID resource)
one other visual name is supported in the programs
list:
default-n
This is like default, but also requests the use
of the default colormap, instead of a private
colormap. (That is, it behaves as if the
-no-install command-line option was specified,
but only for this particular hack.) This is
provided because some third-party programs that
draw on the root window (notably: xv(1), and
xearth(1)) make assumptions about the visual
and colormap of the root window: assumptions
which xscreensaver can violate.
If you specify a particular visual for a program,
and that visual does not exist on the screen, then
that program will not be chosen to run. This means
that on displays with multiple screens of different
depths, you can arrange for appropriate hacks to be
run on each. For example, if one screen is color
and the other is monochrome, hacks that look good in
mono can be run on one, and hacks that only look
good in color will show up on the other.
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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...)
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.
sgiSaverExtension (class Boolean)
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 avail-
able 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
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available, it is flaky (and it also makes the fade
option not work properly.) Use of this extension is
strongly discouraged. Support for it will probably
be removed eventually.
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 sys-
tems, 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 compet-
ing 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 sys-
tems 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)
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The background color used for the stdout/stderr
text, if captureStderr is true. Default: Black.
bourneShell (class BourneShell)
The pathname of the shell that xscreensaver uses to
start subprocesses. This must be whatever your
local variant of /bin/sh is: in particular, it must
not be csh.
ENVIRONMENT
DISPLAY to get the default host and display number, and to
inform the sub-programs of the screen on which to
draw.
XSCREENSAVER_WINDOW
Passed to sub-programs to indicate the ID of the
window on which they should draw on. This is neces-
sary on Xinerama/RANDR systems where multiple physi-
cal 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 cO 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
2009 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.
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AUTHOR
Jamie Zawinski . Written in late 1991; version
1.0 posted to comp.sources.x on 17-Aug-1992.
Please let me know if you find any bugs or make any improve-
ments.
ACKNOWLEDGEMENTS
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 pass-
words and locking-disabled diagnostics.
Thanks to Patrick Moreau for the VMS port.
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.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | desktop/xscreensaver |
|_____________________________|_____________________________|
| Interface Stability | Volatile |
|_____________________________|_____________________________|
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