Many…
Still again, the dilemma: package vs source code… Pymol has lots of dependencies which make compiling quite a work. However, it is popular enough in the community that a quite recent Ubuntu package exists. To install Pymol the Impilo way, I did the following:
apt-get
:% sudo apt-get -y install pymol
/usr/share/applications/pymol.desktop
file to add a line at the very end of the file:NoDisplay=True
% sudo xfce4-menueditor /etc/xdg/xfce4/desktop/menu.xml