Desktop entries

The freedesktop Desktop Entry specification provides a standard for applications to integrate into a desktop environment. Desktop entries are the configuration files that describe how an application is launched and which data it can handle. They also configure how an application appears in a menu with an icon, which is subject to the related menu specification standard.

The most common desktop entries are the .desktop and .directory files. This article explains briefly how to create useful and standard compliant desktop entries. It is mainly intended for package contributors and maintainers, but may also be useful for software developers and others.

There are roughly three types of desktop entries:

Application 

a shortcut to an application

Link 

a shortcut to a web link.

Directory 

a container of meta data of a menu entry

The following sections will roughly explain how these are created and validated.

Related to this content, and also defined in .desktop files, are MIME-type associations for data files. Default applications describes how these are configured.

Application entry

Desktop entries for applications, or .desktop files, are generally a combination of meta information resources and a shortcut of an application. These files usually reside in /usr/share/applications or /usr/local/share/applications for applications installed system-wide, or ~/.local/share/applications for user-specific applications. User entries take precedence over system entries.

File example

Following is an example of its structure with additional comments. The example is only meant to give a quick impression, and does not show how to utilize all possible entry keys. The complete list of keys can be found in the freedesktop.org specification.

[Desktop Entry]

# The type as listed above
Type=Application

# The version of the desktop entry specification to which this file complies
Version=1.0

# The name of the application
Name=jMemorize

# A comment which can/will be used as a tooltip
Comment=Flash card based learning tool

# The path to the folder in which the executable is run
Path=/opt/jmemorise

# The executable of the application, possibly with arguments.
Exec=jmemorize

# The name of the icon that will be used to display this entry
Icon=jmemorize

# Describes whether this application needs to be run in a terminal or not
Terminal=false

# Describes the categories in which this entry should be shown
Categories=Education;Languages;Java;

Key definition

All Desktop recognized desktop entries can be found on the freedesktop.org site. For example, the Type key defines three types of desktop entries: Application (type 1), Link (type 2) and Directory (type 3).

• Version key does not stand for the version of the application, but for the version of the desktop entry specification to which this file complies.

• Name, GenericName and Comment often contain redundant values in the form of combinations of them, like:

Name=Pidgin Internet Messenger
GenericName=Internet Messenger

or

Name=NoteCase notes manager
Comment=Notes Manager

This should be avoided, as it will only be confusing to users. The Name key should only contain the name, or maybe an abbreviation/acronym if available.

• GenericName should state what you would generally call an application that does what this specific application offers (i.e. Firefox is a "Web Browser").
• Comment is intended to contain any usefull additional information.

Deprecation

There are quite some keys that have become deprecated over time as the standard has matured. The best/simplest way is to use the tool desktop-file-validate which is part of the package desktop-file-utils. To validate, run

$ desktop-file-validate <your desktop file>

This will give you very verbose and useful warnings and error messages.

Icons

See also the Icon Theme Specification.

Common image formats

Here is a short overview of image formats commonly used for icons.

Support for image formats for icons as specified by the freedesktop.org standard.

Extension	Full Name and/or Description	Graphics Type	Container Format	Supported
.png	Portable Network Graphics	Raster	No	Yes
.svg(z)	Scalable Vector Graphics	Vector	No	Yes (optional)
.xpm	X PixMap	Raster	No	Yes (deprecated)
.gif	Graphics Interchange Format	Raster	No	No
.ico	MS Windows Icon Format	Raster	Yes	No
.icns	Apple Icon Image	Raster	Yes	No

Converting icons

If you stumble across an icon which is in a format that is not supported by the freedesktop.org standard (like gif or ico), you can use the convert tool (which is part of the imagemagick package) to convert it to a supported/recommended format, e.g.:

$ convert <icon name>.gif <icon name>.png

If you convert from a container format like ico, you will get all images that were encapsulated in the ico file in the form <icon name>-<number>.png. If you want to know the size of the image, or the number of images in a container file like ico you can use the identify tool (also part of the imagemagick package):

$ identify /usr/share/vlc/vlc48x48.ico

/usr/share/vlc/vlc48x48.ico[0] ICO 32x32 32x32+0+0 8-bit DirectClass 84.3kb
/usr/share/vlc/vlc48x48.ico[1] ICO 16x16 16x16+0+0 8-bit DirectClass 84.3kb
/usr/share/vlc/vlc48x48.ico[2] ICO 128x128 128x128+0+0 8-bit DirectClass 84.3kb
/usr/share/vlc/vlc48x48.ico[3] ICO 48x48 48x48+0+0 8-bit DirectClass 84.3kb
/usr/share/vlc/vlc48x48.ico[4] ICO 32x32 32x32+0+0 8-bit DirectClass 84.3kb
/usr/share/vlc/vlc48x48.ico[5] ICO 16x16 16x16+0+0 8-bit DirectClass 84.3kb

As you can see, the example ico file, although its name might suggest a single image of size 48x48, contains no less than 6 different sizes, of which one is even greater than 48x48, namely 128x128.

Alternatively, you can use icotool (from icoutils) to extract png images from ico container:

$ icotool -x <icon name>.ico

For extracting images from .icns container, you can use icns2png (provided by libicns^AUR):

$ icns2png -x <icon name>.icns

Obtaining icons

Although packages that already ship with a .desktop file most certainly contain an icon or a set of icons, there is sometimes the case when a developer has not created a .desktop file, but may ship icons, nonetheless. So a good start is to look for icons in the source package. You can i.e. first filter for the extension with find and then use grep to filter further for certain buzzwords like the package name, "icon", "logo", etc, if there are quite a lot of images in the source package.

$ find /path/to/source/package -regex ".*\.\(svg\|png\|xpm\|gif\|ico\)$"

If the developers of an application do not include icons in their source packages, the next step would be to search on their web sites. Some projects, like i.e. tvbrowser have an artwork/logo page where additional icons may be found. If a project is multi-platform, there may be the case that even if the linux/unix package does not come with an icon, the Windows package might provide one. If the project uses a Version control system like CVS/SVN/etc. and you have some experience with it, you also might consider browsing it for icons. If everything fails, the project might simply have no icon/logo yet.

Tools

gendesk

gendesk started as an Arch Linux-specific tool for generating .desktop files by fetching the needed information directly from PKGBUILD files. Now it is a general tool that takes command-line arguments.

Icons can be automatically downloaded from openiconlibrary, if available. (The source for icons can easily be changed in the future).

How to use

• Add gendesk to makedepends

• Start the prepare() function with:

gendesk --pkgname "$pkgname" --pkgdesc "$pkgdesc"

• Alternatively, if an icon is already provided ($pkgname.png, for instance). The -n flag is for not downloading an icon or using the default icon. Example:

gendesk -n --pkgname "$pkgname" --pkgdesc "$pkgdesc"

• $srcdir/$pkgname.desktop will be created and can be installed in the package() function with:

install -Dm644 "$pkgname.desktop" "$pkgdir/usr/share/applications/$pkgname.desktop"

• The icon can be installed with:

install -Dm644 "$pkgname.png" "$pkgdir/usr/share/pixmaps/$pkgname.png"

• Use --name='Program Name' for choosing a name for the menu entry.

• Use --exec='/opt/some_app/elf --some-arg --other-arg' for setting the exec field.

• See the gendesk project for more information.

List or search in .desktop files

lsdesktopf^AUR can list available .desktop files or search their contents.

$ lsdesktopf
$ lsdesktopf --list
$ lsdesktopf --list gtk zh_TW,zh_CN,en_GB

It can also perform MIME-type-related searches. See Default applications#lsdesktopf.

fbrokendesktop

The fbrokendesktop^AUR bash script using command which to detect broken Exec that points to not existing path. Without any parameters it uses preset folders in DskPath array. It shows only broken .desktop with full path and filename that is missing.

Examples

$ fbrokendesktop
$ fbrokendesktop /usr
$ fbrokendesktop /usr/share/apps/kdm/sessions/icewm.desktop

Tips and tricks

Run a desktop file from a terminal

Install the dex package and run dex /path/to/application.desktop.

Hide desktop entries

Firstly, copy the desktop entry file in question to ~/.local/share/applications to avoid your changes being overwritten.

Then, to hide the entry in all environments, open the desktop entry file in a text editor and add the following line: NoDisplay=true.

To hide the entry in a specific desktop, add the following line to the desktop entry file: NotShowIn=desktop-name

where desktop-name can be option such as GNOME, Xfce, KDE etc. A desktop entry can be hidden in more than desktop at once - simply separate the desktop names with a semi-colon.

Autostart

If you use an XDG Autostart-compliant desktop environment, it will automatically start Desktop entries found in specific directories.

Modify environment variables

Edit the Exec command by prepending env, for example:

~/.local/share/applications/abiword.desktop

Exec=env LANG=he_IL.UTF-8 abiword %U

See also

• DeveloperWiki:Removal of desktop files
• desktop wikipedia article
• information for developers