Today, I was "playing" with the Linux configuration (as usually) and using tasksel on my Debian I remove the Desktop section, and installed it again, when I tried to use startx I just could not, there was no startx command.

After reading a while I found that I needed to install xinit package to have startx in my machine.

so:

sudo aptitude install xinit

once it is installed you have to create or edit your

$HOME/.xinitrc file, and write in there

something like this:

#!/bin/sh
exec startfluxbox
#exec gnome-session
#exec startkde

be sure to have only one Desktop uncommented.