How to set default apps in Chromium / Chrome / Firefox / Ubuntu Linux
Situation: You hate the default app that opens when you double click a file or when you open it with chromium browser and you want to change it.
In Unity (and probably Gnome 3 Shell), some default apps can be changed through
gnome-control-center: System settings > System info > Default applications
You can also right-click on a file > select Properties > Open with. See what applications/programs are listed there. You can also add them and set them as default.
If none of the above work, you can use
xdg-mime) to set a default application for a specific Mime Type
First, you have to figure out what text string to use as a "mime type". An easy way to find it is to look into the default application's desktop file.
Example: Chromium opens magnet links and bittorrent files with
transmission-gtk by default. You want to use deluge. The .desktop files are usually in folder
/usr/share/applications/. We use the
cat command to look into the file
/usr/share/applications/transmission-gtk (a line that starts with "MimeType"):
$ grep 'MimeType' /usr/share/applications/transmission-gtk.desktop
Bingo! x-scheme-handler/magnet and application/x-bittorrent are the mime types we're after.
How to use the
xdg-mime command? Simple:
xdg-mime default myapp.desktop mymimetype
..where we substitute myapp.desktop and mymimetype with the values from above.
Following the example above, we want magnet links and bittorrent files to open with Deluge (
deluge-gtk) application. First you have to install the
deluge-gtk package (otherwise the .desktop file won't exist). Then you have to execute:
xdg-mime default deluge.desktop x-scheme-handler/magnet
xdg-mime default deluge.desktop application/x-bittorrent
grep -i deluge ~/.local/share/applications/*
The last command (
grep) should return "application/x-bittorrent=deluge.desktop" and the other mime type for magnet. Otherwise, something went wrong (maybe the desktop file didn't exist?).
And that's about it! Close and open chromium-browser again (or logout/login).
For the sake of documentation, the files that have to do with mime types and default apps are: