Xnested

I wanted to take some screenshots from Ubuntu for some educational material I am writing. I was wondering how I could take a screenshot on login without running Ubuntu in a virtual environment.

I found xnest. xnest runs a x server inside the running x server. Installed by:

$ sudo apt-get install xnest

Then I used the command gdmflexiserver to start a GDM inside of xnest:

$ gdmflexiserver -n

I noticed that I could not login as the same user that had started gdmflexiserver. I created a new account on my computer and login went fine.