Keys are either OPTIONAL or REQUIRED. If a key is OPTIONAL it may or may not be present in the file. However, if it isn't, the implementation of the standard should not blow up, it must provide some sane defaults.
Some keys only make sense in the context when another particular key
is also present and set to a specific value. Those keys should not be
used if the particular key is not present or not set to the specific
value. For example, the Terminal key can only be used
when the value of the Type key is
Application.
If a REQUIRED key is only valid in the context of another key set to a
specific value, then it has to be present only if the other key is set to
the specific value. For example, the URL key has to be
present when and only when when the value of the Type
key is Link.
Some example keys: Name[C], Comment[it].
Table 2. Standard Keys
| Key | Description | Value Type | REQ? | Type |
|---|---|---|---|---|
Type |
This specification defines 3 types of desktop entries:
Application (type 1),
Link (type 2)
and Directory (type 3).
To allow the addition of new types in the future,
implementations should ignore desktop entries with an
unknown type.
| string | YES | |
Version |
Version of the Desktop Entry Specification that the
desktop entry conforms with. Entries that confirm with this
version of the specification should use 1.0.
Note that the version field is not required to be present.
| string | NO | 1-3 |
Name |
Specific name of the application, for example "Mozilla". | localestring | YES | 1-3 |
GenericName |
Generic name of the application, for example "Web Browser". | localestring | NO | 1-3 |
NoDisplay |
NoDisplay means "this application exists, but don't display it in the menus".
This can be useful to e.g. associate this application with MIME types, so that
it gets launched from a file manager (or other apps), without having a menu
entry for it (there are tons of good reasons for this, including e.g. the
netscape -remote, or kfmclient openURL kind of stuff).
| boolean | NO | 1-3 |
Comment |
Tooltip for the entry, for example "View sites on the
Internet". The value should not be redundant with the values of
Name and GenericName.
| localestring | NO | 1-3 |
Icon |
Icon to display in file manager, menus, etc. If the name is an absolute path, the given file will be used. If the name is not an absolute path, the algorithm described in the Icon Theme Specification will be used to locate the icon. | localestring | NO | 1-3 |
Hidden |
Hidden should have been called Deleted.
It means the user deleted (at his level)
something that was present (at an upper level, e.g. in the system dirs). It's
strictly equivalent to the .desktop file not existing at all, as far as that user is
concerned. This can also be used to "uninstall" existing files (e.g. due to a renaming)
- by letting make install install a file with Hidden=true in it.
| boolean | NO | 1-3 |
OnlyShowIn, NotShowIn |
A list of strings identifying the environments that should
display/not display a given desktop entry. Only one of
these keys, either OnlyShowIn or
NotShowIn, may appear in a group (for
possible values see the Desktop
Menu Specification).
| string(s) | NO | 1-3 |
TryExec | Path to an executable file on disk used to determine if the program is actually installed. If the path is not an absolute path, the file is looked up in the $PATH environment variable. If the file is not present or if it is not executable, the entry may be ignored (not be used in menus, for example). | string | NO | 1 |
Exec | Program to execute, possibly with arguments. | string | YES | 1 |
Path |
If entry is of type Application, the working directory to run the program in.
| string | NO | 1 |
Terminal | Whether the program runs in a terminal window. | boolean | NO | 1 |
MimeType | The MIME type(s) supported by this application. | string(s) | NO | 1 |
Categories | Categories in which the entry should be shown in a menu (for possible values see the Desktop Menu Specification). | string(s) | NO | 1 |
StartupNotify | If true, it is KNOWN that the application will send a "remove" message when started with the DESKTOP_STARTUP_ID environment variable set. If false, it is KNOWN that the application does not work with startup notification at all (does not shown any window, breaks even when using StartupWMClass, etc.). If absent, a reasonable handling is up to implementations (assuming false, using StartupWMClass, etc.). (See the Startup Notification Protocol Specification for more details). | boolean | NO | 1 |
StartupWMClass | If specified, it is known that the application will map at least one window with the given string as its WM class or WM name hint (see the Startup Notification Protocol Specification for more details). | string | NO | 1 |
URL | If entry is Link type, the URL to access. | string | YES | 2 |
Exec key
The Exec key must contain a command line.
A command line consists of an executable program optionally followed
by one or more arguments.
The executable program can either be specified with its full path or
with the name of the executable only. If no full path is provided the
executable is looked up in the $PATH environment variable used by the
desktop environment.
The name or path of the executable program may not contain the equal
sign ("="). Arguments are separated by a space.
Arguments may be quoted in whole. If an argument contains a reserved character the argument must be quoted. The rules for quoting of arguments is also applicable to the executable name or path of the executable program as provided.
Quoting must be done by enclosing the argument between double quotes and escaping the double quote character, backtick character ("`"), dollar sign ("$") and backslash character ("\") by preceding it with an additional backslash character. Implementations must undo quoting before expanding field codes and before passing the argument to the executable program. Reserved characters are space (" "), tab, newline, double quote, single quote ("'"), backslash character ("\"), greater-than sign (">"), less-than sign ("<"), tilde ("~"), vertical bar ("|"), ampersand ("&"), semicolon (";"), dollar sign ("$"), asterisk ("*"), question mark ("?"), hash mark ("#"), parenthesis ("(") and (")") and backtick character ("`").
Note that the general escape rule for values of type string states that the backslash character can be escaped as ("\\") as well and that this escape rule is applied before the quoting rule. As such, to unambiguously represent a literal backslash character in a quoted argument in a desktop entry file requires the use of four successive backslash characters ("\\\\"). Likewise, a literal dollar sign in a quoted argument in a desktop entry file is unambiguously represented with ("\\$").
A number of special field codes have been defined which will be
expanded by the file manager or program launcher when encountered
in the command line.
Field codes consist of the percentage character ("%") followed by
an alpha character. Literal percentage characters must be escaped
as %%.
Deprecated field codes should be removed from the command line and
ignored.
Field codes are expanded only once, the string that is used to
replace the field code should not be checked for field codes itself.
Command lines that contain a field code that is not listed in this specification are invalid and must not be processed, in particular implementations may not introduce support for field codes not listed in this specification. Extensions, if any, should be introduced by means of a new key.
Implementations must take care not to expand field codes into multiple arguments unless explicitly instructed by this specification. This means that name fields, filenames and other replacements that can contain spaces must be passed as a single argument to the executable program after expansion.
Although the Exec key is defined to have a value
of the type string, which is limited to ASCII characters, field code
expansion may introduce non-ASCII characters in arguments.
Implementations must take care that all characters in arguments
passed to the executable program are properly encoded according to
the applicable locale setting.
Recognized field codes are as follows:
| Code | Description |
|---|---|
%f |
A single file name, even if multiple files are selected. The system
reading the desktop entry should recognize that the program in
question cannot handle multiple file arguments, and it should
should probably spawn and execute multiple copies of a program
for each selected file if the program is not able to handle
additional file arguments. If files are not on the local file system
(i.e. are on HTTP or FTP locations), the files will be copied to the local
file system and %f will be expanded to point at the temporary
file. Used for programs that do not understand the URL syntax.
|
%F | A list of files. Use for apps that can open several local files at once. Each file is passed as a separate argument to the executable program. |
%u | A single URL. Local files may either be passed as file: URLs or as file path. |
%U | A list of URLs. Each URL is passed as a separate argument to the executable program. Local files may either be passed as file: URLs or as file path. |
%d | Deprecated. |
%D | Deprecated. |
%n | Deprecated. |
%N | Deprecated. |
%i |
The Icon key of the desktop entry
expanded as two arguments, first
--icon and then the value of the
Icon key. Should not expand to any
arguments if the Icon key is empty
or missing.
|
%c |
The translated name of the application as listed in
the appropriate Name key in the
desktop entry.
|
%k | The location of the desktop file as either a URI (if for example gotten from the vfolder system) or a local filename or empty if no location is known. |
%v | Deprecated. |
%m | Deprecated. |
A command line may contain at most one %f, %u, %F or %U field code. If the application should not open any file the %f, %u, %F and %U field codes must be removed from the command line and ignored.
Field codes must not be used inside a quoted argument, the result of field code expansion inside a quoted argument is undefined. The %F and %U field codes may only be used as an argument on their own.
The MimeType key is used to indicate the MIME
Types that an application knows how to handle. It is expected that
for some applications this list could become long. An application
is expected to be able to reasonably open files of these types
using the command listed in the Exec key.
There should be no priority for MIME Types in this field, or any
form of priority in the desktop file. Priority for applications
is handled external to the .desktop files.
As this standard is quite old there are some deprecated items that may or may not be used by several implementations.
Type=MimeType is deprecated as there is a
new standard for this now, see the Shared
MIME-info Database specification for more
information. In consequence the Keys
Patterns (various file name extensions
associated with the MIME type) and
DefaultApp (the default application
associated with this MIME type) are also deprecated.
Using .kdelnk instead of
.desktop as the file extension is
deprecated.
Using [KDE Desktop Entry] instead of
[Desktop Entry] as header is deprecated.
The Encoding key is deprecated. It was used to
specify whether keys of type localestring were
encoded in UTF-8 or in the specified locale. Possible values are
UTF-8 and Legacy-Mixed. See
Appendix D, The Legacy-Mixed Encoding (Deprecated) for more details.
Deprecated Exec field codes:
%m (the mini-icon associated with the
desktop entry, this should be expanded as two arguments,
--miniicon and the content of the
MiniIcon key, it can also be ignored by
expanding it to no arguments), %v (the device as listed
in the Dev key in the desktop file),
%d (the directory of a file), %D (the directories of
files), %n (the base name of a file) and %N (the base names
of files).
Deprecated keys: MiniIcon (small icon for
menus, etc.), TerminalOptions (if the
program runs in a terminal, any options that should be
passed to the terminal emulator before actually executing
the program), Protocols,
Extensions,
BinaryPattern,
MapNotify.
The SwallowTitle and
SwallowExec keys are deprecated.
The SwallowTitle key is of type
localestring and specifies the title of the window
if is swallowed onto the panel. The SwallowExec
key is of type string and specifies the
program to exec if swallowed app is clicked.
The SortOrder key is deprecated. It is of type
string(s) and may be used to specify the order in
which to display files. The Desktop
Menu Specification defines another mechanism for defining the
order of menu items.
The FilePattern key is deprecated.
The value is a list of regular
expressions to match against for a file manager to determine if this
entry's icon should be displayed. Usually simply the name of the main
executable and friends.
Historically some booleans have been represented by the numeric
entries 0 or 1. With
this version of the standard they are now to be represented as a
boolean string. However, if an implementation is reading a pre-1.0
desktop entry, it should interpret 0 and
1 as false and
true, respectively.
Historically lists have been comma separated. This is inconsistent with other lists which are separated by a semicolon. When reading a pre-1.0 desktop entry, comma separated lists should continue to be supported.