ubuntu 设置默认值 VLC / LibreOffice 等
Associate all audio and video files to VLC instead of Totem media player (Movie Player)

?

Video files: .avi .mp4 .mpg .ogv .ogm .mkv .wmv etc.
Audo files: .mp3 .ogg .flac .wav .wma etc.

?

Open defaults.list with gedit:

?
Save the modified file, and you're done! Change are effective immediately.
?
?
Associate all office documents to LibreOffice instead of OpenOffice.org or Abiword
?
Office files:? .odt? .ods.? .doc? .docx? .xls? .xlsx? etc.
?
Open defaults.list with gedit:
(Search → Replace → Replace All)
?
Finally, save the file. No need to restart, you're all set!
?
Ubuntu's case
For an obscure reason, changing the file associations directly in the defaults.list doesn't seem to work Ubuntu 10.10 "Maverick Meerkat". Nevertheless, importing information to the the mimeapps.list works.
?
The file associations for each user are stored in:
gedit ~/.local/share/applications/mimeapps.list
?
And replace all occurences of totem with vlc (Search → Replace...) Proceed similarly for audio files if needed.
?
?
来源： http://www.libre-software.net/change-the-default-application-linux-mint-ubuntu
?