update-desktop-database [-q|--quiet] [-v|--verbose] [DIRECTORY...]
The update-desktop-database program is a tool to build a cache database of the MIME types handled by desktop files.
The cache database contains the list of MIME types that can be handled by desktop files, as well as, for each MIME type, a list of desktop files that can handle this MIME type. This cache database ease the work of applications that need to find an application that can open a document of a specific MIME type: those applications will not have to parse all the desktop files existing on the system, and can instead parse this cache database.
If no DIRECTORY is specified as argument, the desktop files that will be processed are the ones installed in $XDG_DATA_DIRS/applications.
If both the --quiet and --verbose options are used, then --verbose will be ignored.
The following options are supported:
If an invalid MIME type is met, it will be ignored and the creation of the cache database will continue.
The format of the cache database is a simple desktop entry format, with a MIME Cache group, containing one key per MIME type. The key name is the MIME type, and the key value is the list of desktop file that can handle this MIME type.
The order of the desktop files found for a MIME type is not significant. Therefore, an external mechanism must be used to determine what is the preferred desktop file for a MIME type.
Here is a simple example of a cache database:
This cache database is created with three desktop files, each containing a MimeType key:
If you find bugs in the update-desktop-database program, please report these on https://bugs.freedesktop.org.