How to change your default applications (Mail Client) in a Gnome Desktop

The Gnome desktop comes with a couple of default applications like Evolution Mail, Rhythmbox Music Player, GNOME Terminal and others, but many users give-them-up for other “better” applications. In most cases the non expert Gnome user continues to maintain as default those applications they don’t even use. Examples of users with Evolution Mail as default whilst using Thunderbird are many, just like those who have Rhythmbox Music Player as default but use VLC Media Player (that without any configuration plays DVD, VCD, MPEG-1, MPEG-2, MPEG-4, DivX, mp3, ogg) or Amarok, others have the Gnome Terminal as default but use aterm or Terminator.

So how do we get about changing our default applications?
In most cases you can do so from the Preferred Applications manager: System -> Preferences -> Preferred Applications
Therein; On the “Internet” tab, simply select “Thunderbird” from the drop down menu. If it is not present then Select “Custom” and type in the command box “thunderbird %s” (without quotes )

If you do not find these menus then you could still make use of the GNOME Configuration Editor.
-> From the command-line run “gconf-editor”
-> Move to /desktop/gnome/applications/url-handlers/mailto
-> Right-click on “command” field and Click on “Edit Key” and modify to thunderbird %s — for example

-> Check the “enable” field
-> Uncheck the “needs_terminal” field
-> Close it and you’re done.

On the “System” tab you can choose “Custom” as your terminal emulator. Enter “terminator” as the command, and “-e” as the execute flag. On GNOME 2.21 or later, “Terminator” will already be an available option, supposing you have “nautilus-open-terminal” package installed.

The nautilus-open-terminal offers a quick launch of the default terminal(in this case Terminator) with a right-click within nautilus or the gnome-desktop area. After installation [sudo aptitude install nautilus-open-terminal] it might be necessary to restart gnome for nautilus-open-terminal to be effective.

On the “Multimedia” tab you can replace Totem Movie Player by simply typing amarok or vlc, after choosing “Custom” in the drop down menu.
Same can be done by Right-clicking on an audio file -> Open With -> Open with Other Application…
In the “Open Window” choose the application you want to use with the audio file.

How to set your preferred Email Client for Firefox in Linux

It could also be very convenient to change default email client for Firefox from Evolution to say Thunderbird or what ever.

-> In Firefox’s Location Bar, type about:config and hit Enter
-> Right-click on the body.
-> From the pop-up menu, select “New” -> “String”
-> In the pop-up dialog box “Enter the preference name”, enter
network.protocol-handler.app.mailto
and click “OK”

-> In the pop-up dialog box “network.protocol-handler.app.mailto”, enter /usr/bin/thunderbird (or the filesystem location of your email client ) and click “OK”
To test your new default Firefox email client, go to File -> Send Link and your preferred email client should open.