NAME¶

xscreensaver - extensible screen saver and screen locking framework

SYNOPSIS¶

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

DESCRIPTION¶

XScreenSaver waits until the user is idle, and then runs graphics demos chosen at random. It can also lock your screen, and provides configuration and control of display power management.

XScreenSaver is also available on macOS, iOS and Android.

GETTING STARTED¶

XScreenSaver is a daemon that runs in the background. You configure it with the xscreensaver-settings(1) program.

	xscreensaver &
	xscreensaver-settings

HOW IT WORKS¶

When it is time to activate the screensaver, a full-screen black window is created that covers each monitor. A sub-process is launched for each one running a graphics demo, pointed at the appropriate window. Because of this, any program which can draw on a provided window can be used as a screensaver. The various graphics demos are, in fact, just standalone programs that do that.

When the user becomes active again, the screensaver windows are unmapped, and the running subprocesses are killed.

The display modes are run at a low process priority, and spend most of their time sleeping/idle by default, so they should not consume significant system resources.

COMMAND-LINE OPTIONS¶

--display host:display.screen

The X display to use. For displays with multiple screens, XScreenSaver will manage all screens on the display simultaneously.

--verbose

Print diagnostics to stderr.

--version

Print the version number and exit.

--log filename

Append all diagnostic output to the given file. This also implies --verbose. Use this when reporting bugs.

--no-splash

Don't display the splash screen at startup.

POWER MANAGEMENT¶

The xscreensaver-settings(1) program is where you configure if and when your monitor should power off. It saves the settings in your ~/.xscreensaver file. Do not use xset(1) to manually change the power management settings, that won't work.

When the monitor is powered down, the display hacks will stop running (though it may take a minute or two for XScreenSaver to notice).

LAPTOP LIDS¶

If your system uses systemd(1) or elogind(8), then closing the lid of your laptop will cause the screen to lock immediately.

If not, then the screen might not lock until a few seconds after you re-open the lid. Which is less than ideal. So if you do not have systemd(1), you might want to get in the habit of manually locking your screen before closing the lid (xscreensaver-command --lock).

PLAYING VIDEOS¶

Likewise, if you have systemd(1) or elogind(8), then all of the popular video players and web browsers will prevent XScreenSaver from blanking the screen while video is playing.

Both of these features require that xscreensaver-systemd(6) be able connect to D-Bus.

INSTALLATION¶

Each desktop environment has its own system for launching long-running daemons like XScreenSaver, and since many of them come bundled with their own (buggy, insecure, inferior) screen-locking frameworks, it is also necessary to disable those other frameworks before XScreenSaver can work.

	systemctl --user enable xscreensaver

	Name: XScreenSaver
	Command: xscreensaver
	Comment: XScreenSaver

	Greeter=/usr/bin/gdmlogin
	BackgroundProgram=xscreensaver --nosplash
	RunBackgroundProgramAlways=true

THE WAYLAND PROBLEM¶

Wayland is a completely different window system that is intended to replace X11. After 14+ years of trying, some Linux distros have finally begun enabling it by default. Most deployments of it also include XWayland, which is a compatibility layer that allows some X11 programs to continue to work within a Wayland environment.

Unfortunately, XScreenSaver is not one of those programs.

If your system is running XWayland, XScreenSaver will malfunction in two ways:

In short, for XScreenSaver to work properly, you will need to switch off Wayland and use the X Window System like in the "good old days".

	WaylandEnable=false

	SessionDir=/dev/null

SECURITY CONCERNS¶

XScreenSaver has a decades-long track record of securely locking your screen. However, there are many things that can go wrong. X11 is a very old system, and has a number of design flaws that make it susceptible to foot-shooting.

	echo 2 > /proc/sys/vm/overcommit_memory
	echo vm.overcommit_memory = 2 >> /etc/sysctl.conf

	sudo systemctl disable --now systemd-oomd
	sudo systemctl mask systemd-oomd

MULTI-USER OR SITE-WIDE CONFIGURATION¶

For a single user, the proper way to configure XScreenSaver is to simply run the xscreensaver-settings(1) program, and change the settings through the GUI. Changes are written to the ~/.xscreensaver file.

If you want to set the system-wide defaults, then make your edits to /etc/X11/app-defaults/XScreenSaver instead. The two files have similar (but not identical) syntax.

You can also make changes via the X Resource Database and xrdb(1), but that can be very confusing and is not really recommended.

Options in ~/.xscreensaver override any settings in the resource database or app-defaults file.

If you change a setting in the .xscreensaver file while XScreenSaver is already running, it will notice this, and reload the file as needed. But if you change a setting in the X Resource Database, you will need to restart XScreenSaver for those changes to take effect:

	xrdb < ~/.Xdefaults
	xscreensaver-command --restart

X RESOURCES¶

These are the X resources use by XScreenSaver program. You probably won't need to change these manually: that's what the xscreensaver-settings(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.

If there are multiple screens, the savers are staggered slightly so that while they all change every cycle minutes, they don't all change at the same time.

lock (class Boolean)

Enable locking: before the screensaver will turn off, it will require you to type the password of the logged-in user.

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, lockTimeout 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). A few seconds are added each time you type a character.

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.

verbose (class Boolean)

Whether to print diagnostics. Default false.

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.

demoCommand (class DemoCommand)

This is the shell command run when the Demo button on the splash window is pressed. It defaults to xscreensaver-settings(1).

newLoginCommand (class NewLoginCommand)

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

nice (class Nice)

The sub-processes launched 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 desktop will fade to black instead of simply winking out. Default: true.

unfade (class Boolean)

If this is true, then when the screensaver deactivates, desktop will fade back ininstead of appearing immediately. This is only done if fade is true as well. Default: true.

fadeSeconds (class Time)

If fade is true, this is how long the fade will be in seconds. Default 3 seconds.

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-settings(1) program will suppress the non-existent programs from the list if this is true. Default: false.

authWarningSlack (class Integer)

After you successfully unlock the screen, a dialog may pop up informing you of previous failed login attempts. If all of those login attemps were within this amount of time, they are ignored. The assumption is that incorrect passwords entered within a few seconds of a correct one are user error, rather than hostile action. Default 20 seconds.

mode (class Mode)

Controls the screen-saving behavior. Valid values are:

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-settings(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-settings(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.

The default XScreenSaver hacks directory (typically /usr/libexec/xscreensaver/) is prepended to $PATH before searching for these programs.

To use a program as a screensaver, it must be able to render onto the window provided to it in the $XSCREENSAVER_WINDOW environment variable. If it creates and maps its own window instead, it won't work. It must render onto the provided window. 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        \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:

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.

visualID (class VisualID)

This is an historical artifact left over from when 8-bit displays were still common. You should probably ignore this.

Specify which X visual to use by default. (Note carefully that this resource is called visualID, not merely visual; if you set the visual resource instead, things will malfunction in obscure ways for obscure reasons.)

Valid values for the VisualID resource are:

installColormap (class Boolean)

This is an historical artifact left over from when 8-bit displays were still common. On PseudoColor (8-bit) displays, install a private colormap while the screensaver is active, so that the graphics hacks can get as many colors as possible. This is the default. (This only applies when the screen's default visual is being used, since non-default visuals get their own colormaps automatically.) This can also be overridden on a per-hack basis: see the discussion of the default-n name in the section about the programs resource.

This does nothing if you have a TrueColor (16-bit or deeper) display. (Which, in this century, you do.)

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.

A single pixel of motion will still cause the monitor to power back on, but not un-blank. This is because the X11 server itself unfortunately handles power-management-related activity detection rather than XScreenSaver.

BUGS¶

https://www.jwz.org/xscreensaver/bugs.html explains how to write the most useful bug reports. If you find a bug, please let me know!

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.

PATH

to find the sub-programs to run, including the display modes.

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 https://www.jwz.org/xscreensaver/

SEE ALSO¶

X(1), Xsecurity(1), xauth(1), xdm(1), gdm(1), xhost(1), systemd(1), elogind(8), xscreensaver-settings(1), xscreensaver-command(1), xscreensaver-systemd(6), xscreensaver-gl-helper(6), xscreensaver-getimage(6), xscreensaver-text(6).

COPYRIGHT¶

Copyright © 1991-2022 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>

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 three decades!