Desktop entry files should have the .desktop
extension, except for files of Type
Directory which should have the
.directory extension. Determining file type on basis
of extension makes determining the file type very easy and quick.
When no file extension is present, the desktop system should
fall back to recognition via "magic detection".
For applications, the part of the name of the desktop file (before the .desktop)
should follow the "reverse DNS" convention, e.g. org.example.FooViewer.desktop.
Desktop entry files are encoded in UTF-8. A file is interpreted as a series of lines that are separated by linefeed characters. Case is significant everywhere in the file.
Compliant implementations MUST not remove any fields from the file, even if they don't support them. Such fields must be maintained in a list somewhere, and if the file is "rewritten", they will be included. This ensures that any desktop-specific extensions will be preserved even if another system accesses and changes the file.
Lines beginning with a # and blank lines are
considered comments and will be ignored, however they should be
preserved across reads and writes of the desktop entry file.
Comment lines are uninterpreted and may contain any character (except for LF). However, using UTF-8 for comment lines that contain characters not in ASCII is encouraged.
A group header with name groupname is a line in the
format:
[groupname]
Group names may contain all ASCII characters except for
[ and ] and control characters.
Multiple groups may not have the same name.
All {key,value} pairs following a group header until
a new group header belong to the group.
The basic format of the desktop entry file requires that there be
a group header named Desktop Entry. There may
be other groups present in the file, but this is the most
important group which explicitly needs to be supported. This
group should also be used as the "magic key" for automatic MIME
type detection. There should be nothing preceding this group in
the desktop entry file but possibly one or more comments.
Entries in the file are {key,value} pairs in the
format:
Key=Value
Space before and after the equals sign should be ignored; the
= sign is the actual delimiter.
Only the characters A-Za-z0-9- may be used in
key names.
As the case is significant, the keys Name and
NAME are not equivalent.
Multiple keys in the same group may not have the same name. Keys in different groups may have the same name.