X

User Quick Start

X session fails to start: Check ~/.xsession-errors
Set your window manager: Edit ~/.xsession (or ~/.Xsession - it doesn't matter which; the first one found is used)
Start some apps: Edit ~/.xsession
Set global environment variables for your X session: Edit ~/.xsessionrc

System Quick Start

Set the default session manager: Change the link for /usr/bin/x-session-manager->/etc/alternatives/x-session-manager->
Set the default window manager: Change the link for /usr/bin/x-window-manager->/etc/alternatives/x-window-manager->
Set the default display manager: Edit /etc/X11/default-display-manager
Set the default pseudo terminal: Change the link for /usr/bin/x-terminal-emulator->/etc/alternatives/x-terminal-emulator->
Restrict users, other session options: Edit /etc/X11/Xsession.options
Stop startx from using Xsession by default: Edit /etc/X11/xinit/xinitrc
Set xdm options: Edit /etc/X11/xdm/xdm-config

Note: ~/.Xresources is different from ~/.Xdefaults-<host_alias> and ~/.Xdefaults
The first one is read (sourced) by the "xserver" from /etc/X11/Xsession.d/30x11-common_xresources the later two are read by the application directly at every startup.

Note that ~/.Xdefaults is a relic from X Version 10 (and X11R1) days, before app-defaults files were implemented. It has been deprecated for well over ten years. ~/.Xresources should be used instead.

Definitions

X session: The combination of an X server and connecting X clients
X server: A program run on a local host connected to the user's display and input devices
X client: A program run on a remote host that processes data and talks to the X server
application server: A program run on a remote host that processes data and talks to the clients. XDM would typically run on an application server, to permit users to logon and run applications from that server
application client: A program run on a local host connected to the user's display and input devices

References

Files

/etc/X11/Xsession: The final call
/etc/X11/Xsession.options: configuration options for /etc/X11/Xsession
/etc/X11/Xsession.d: run-parts like executable files run by Xsession
/etc/X11/default-display-manager: X display manager preference
~/.xsessionrc

~/.gnomerc
~/.gnome2/session

Discussion

XENVIRONMENT
Any user and machine-specific resources may be specified by setting the XENVIRONMENT environment variable to the name of a resource file to be loaded by all applications. If this variable is not defined, a file named $HOME/.Xdefaults-hostname is looked for instead, where hostname is the name of the host where the application is executing.

Examples

user@host:1:~ $ cat .Xdefaults-<hostname>
XTerm*title: ~/.Xdefaults-<hostname>
xterm*faceName:         10x20
xterm*saveLines:        65535
xterm*scrollBar:        true
xterm*rightScrollBar:   true
xterm*loginShell:       true
xterm*toolBar:          false
xterm*background:       blue
xterm*foreground:       yellow

user@host:1:~ $ cat .Xresources
! ~/.Xresources - sourced when xdm starts
XTerm*Font:             10x20
XTerm*Title:            ~/.Xresources
XLoad*Background:       gold
XLoad*Foreground:       red
XLoad*highlight:        black
XLoad*borderWidth:      0
user@host:1:~ $

user@host:1:~ $ cat .Xsession
/usr/bin/xset -dpms s off
/usr/bin/blackbox
user@host:1:~ $

user@host:0:~ $ cat .Xsessionrc
! ~/.Xsessionrc
! Read (sourced) by the X session scripts during login
! Most useful for setting locale information
user@host:0:~ $

user@host:1:~ $ cat .xinitrc
xterm -bg black -fg white &
/usr/bin/blackbox
#/usr/bin/gnome-session
user@host:1:~ $

Note: Complete answers to the following questions are still blowing in the wind:

Why the message: No protocol specified Error: Can't open display: 192.168.1.x:0.0 ? Google for "Can't open display" and I get 76,500 hits. That seems like a large number for a windowing system that prides itself on being client/server so the pieces aren't tied to any particular host. Having fought this problem for years, I am still baffled by this. To run an application on host local.linux and display the results on host remote.linux, the party line goes like this: on remote.linux type xhost + on remote.linux edit /usr/share/gdm/defaults.conf and change DisallowTCP=true to DisallowTCP=false This won't work in Debian because Debian has a /etc/gdm/gdm.conf file that overrides /usr/share/gdm/defaults.conf and it won't work in Ubuntu because Ubuntu doesn't have either of those files. (Desktop 10.10) (gdmsetup on Debian customizes /etc/gdm/gdm.conf) (no clue what gdmsetup customizes on Ubuntu; Ubuntu doesn't have a man page for that) After this, reboot the box (just restarting gdm doesn't seem to work) In addition some people have said to unset DISPLAY on the remote machine. I've found that DISPLAY should be set to :0.0 (At least on Debian) On host local.linux run xclock -display remote.linux:0.0 and the clock is supposed to pop up on remote.linux.

	This site best viewed with a browser
	Warning: This is a Debian centric site and MAY contain peanuts.
	Many thanks to Debra Lynn and Ian Murdock for making Debian possible
	First created Apr 22, 2008 ~ Last revised December 06, 2010

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