Default applications

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Default applications can be set for use with particular file types (e.g. the Firefox web browser for HTML files). Where undertaken, files may be opened and/or edited with the desired application much faster and more conveniently. There are also numerous methods to configure default applications in Linux. This page will explain the most common methods: File Managers, MIME types, and environment variables.

Using File Managers

Tip: This is the recommended method for less experienced users

Most file managers will allow for specific applications to be set as the defaults for various file types. New defaults may also be set at any time. For example, to set a default application using thunar, the native file manager for XFCE:

  • right-click the file-type desired
  • Select Open with another application
  • Select the desired application
  • Ensure that the Use as default for this kind of file check-box is ticked
  • Click the Open button.

The general process will be very similar for most other popular file managers, including PCManFM and spacefm.

Using MIME types and desktop entries

The modern method to start applications is using Desktop Entries. This way, programs can advertise which kind of files (to be exact: what MIME types) they can open. For instance, gimp.desktop states MimeType=image/bmp;image/gif;....

A list of MIME type and corresponding default application is stored in $XDG_DATA_HOME/applications/mimeapps.list (for a single user; $XDG_DATA_HOME defaults to ~/.local/share) and /usr/share/applications/defaults.list (system wide). This list can be edited by using xdg-mime.

This file looks like this:

[Default Applications]
mimetype=desktopfile1;desktopfile2;...;desktopfileN

E.g.

[Default Applications]
text/html=firefox.desktop;chromium.desktop

A distribution could also ship a /usr/share/applications/mimeapps.list to provide system-wide defaults, but Arch Linux does not do this. To override these system-wide defaults, one can add [Added Associations] section is used to specify preferred (default) applications in decreasing order of preference for the specified MIME type. The [Removed Associations] section is used to explicitly remove any previously inherited associations.

gnome-defaults-list

gnome-defaults-listAUR is available from the AUR, and contains a list of file-types and programs specific to the Gnome desktop. The list is installed to /etc/gnome/defaults.list.

Open this file with a text editor. Here you can replace a given application with the name of the program of your choice. For example, the media-player totem can be replaced with another, such as vlc. Save the file to ~/.local/share/applications/defaults.list.

perl-file-mimeinfo

perl-file-mimeinfo is available from the official repositories. It can be invoked by using the following command:

$ mimeopen -d /path/to/file

You are asked which application to use when opening /path/to/file:

Please choose a default application for files of type text/plain
       1) notepad  (wine-extension-txt)
       2) Leafpad  (leafpad)
       3) OpenOffice.org Writer  (writer)
       4) gVim  (gvim)
       5) Other...

Your answer becomes the default handler for that type of file. Mimeopen is installed as /usr/bin/perlbin/vendor/mimetype.

xdg-open

xdg-open is a desktop-independent tool for starting default applications. Many applications invoke the xdg-open command internally. xdg-open uses xdg-mime to query ~/.local/share/applications/mimeapps.list (among other things; if you use a mainstream DE like GNOME, KDE or LXDE, xdg-open might try using their specific tools before xdg-mime) to find the MIME type of the file that is to be opened and the default application associated with that MIME type.

See xdg-open for more information.

Custom file associations

The following method creates a custom mime type and file association manually. This is useful if your desktop does not have a mime type/file association editor installed. In this example, a fictional multimedia application 'foobar' will be associated with all *.foo files. This will only affect the current user.

  • First, create the file ~/.local/share/mime/packages/application-x-foobar.xml:
$ mkdir -p ~/.local/share/mime/packages
$ cd ~/.local/share/mime/packages
$ touch application-x-foobar.xml
  • Then edit ~/.local/share/mime/packages/application-x-foobar.xml and add this text:
<?xml version="1.0" encoding="UTF-8"?>
<mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
	<mime-type type="application/x-foobar">
		<comment>foo file</comment>
		<icon name="application-x-foobar"/>
		<glob-deleteall/>
		<glob pattern="*.foo"/>
	</mime-type>
</mime-info>

Note that you can use any icon, including one for another application.

  • Next, edit or create the file ~/.local/share/applications/foobar.desktop to contain something like:
[Desktop Entry]
Name=Foobar
Exec=/usr/bin/foobar
MimeType=application/x-foobar
Icon=foobar
Terminal=false
Type=Application
Categories=AudioVideo;Player;Video;
Comment=

Note that Categories should be set appropriately for the application type (in this example, a multimedia app).

  • Now update the mime database with:
$ update-mime-database ~/.local/share/mime

Programs that use mime types, such as file managers, should now open *.foo files with foobar. (You may need to restart your file manager to see the change.)

Maintaining settings for multiple desktop environments

The OnlyShowIn field of a .desktop file may be useful; see this page. I haven't tried setting this field yet; please update this wiki page if you have any info about using OnlyShowIn.

Using environment variables

Most non-graphical programs use Environment Variables, such as EDITOR or BROWSER. These can be set in your terminal's autostart file (e.g. ~/.bashrc):

~/.bashrc
export EDITOR="nano"
export BROWSER="firefox"

Troubleshooting

Applications don't appear in the Open With... context menu (of a file manager)

Sometimes, a certain application will not appear in the right-click Open With... dialog. To fix this problem, locate the .desktop file in /usr/share/applications, edit it as root, and add %U to the end of the Exec= line. For example, Kile currently has this problem; you need to edit /usr/share/applications/kde4/kile.desktop and change the line reading Exec=kile to read Exec=kile %U. Also, please file a bug against the upstream project if you notice this problem.

You may also have to edit the MimeType list in the .desktop file if you install extensions that allow an application to handle additional MIME types.