This started happening after an upgrade to Ubuntu 13.04. We have shell scripts here and there saved as .run files, e.g.
Build.linux.auto.run, to automate AVBlocks builds on Linux. Normally Nautilus will ask you whether you want to run the script when you double click a
.run file, but on Ubuntu 13.04, Nautilus suddenly started opening
.run files in Gedit. It turns out there is a setting in Gnome for that. Here is how to fix it:
After upgrading to Ubuntu 12.04.3 LTS, I could not boot in GUI / X anymore. I got this when trying to start X: