Running multiple X11 sessions
Posted by Steve on Tue 18 Jan 2005 at 11:14
For testing out Window managers, or developing applications it's sometimes useful to run more than one X11 Window session. Normally you'd do that by setting up X to run on another virtual terminal, but thats a bit awkward to use, and only works if you're physically in front of the machine. Instead you could run nested X11 sessions.
XNest allows you to start a new X11 session inside your current one, running completely seperate from it.
It's very useful for testing out Window Managers, as you can only have one window manager running at a time.
xnest is usually installed when you setup the X11 window system on Debian machines, but if it's not you can get it by running the following command as root:
apt-get install xnest
Usage is very simple:
Xnest -ac :2
This will create a new window which has the DISPLAY string set to ":2". (The -ac flag allows you to connect to it, and is important).
Once this is done you can run commands that will display inside that by adding "-display :2" to their command line, such as:
xterm -display :2
This will give you an xterm running inside your new X11 environment.
To run a new window manager run:
/etc/alternatives/x-window-manager -display :2
This will give you your default window manager in the new session, which you can use to execute programs, etc.
If you wish to test out a new window manager, such as xfce you can do that by running as root:
apt-get install xfce4
Xnest -ac :22 & export DISPLAY=:22 xfce4-session &
This sets up a new X11 session running as ":22", and then starts a copy of the xfce environment inside it.
If you like it you can set this up as your primary window manager, if not you can just remove it..