# global system configuration
/etc/gnome/defaults.list
# user configuration
#~/.local/share/applications/defaults.list
~/.local/share/applications/mimeapps.list
sed -i 's|totem.desktop|vlc.desktop|g' /etc/gnome/defaults.list
sudo sed -i 's|totem.desktop|vlc.desktop|g' /etc/gnome/defaults.list
image/x-psd=gimp.desktop
# Links
https://help.ubuntu.com/community/AddingMimeTypes
http://www.libre-software.net/change-the-default-application-ubuntu-linux
http://askubuntu.com/questions/289337/how-can-i-change-file-association-globally