Table of Contents
Both the KDE and GNOME desktop environments have adopted a similar format for "desktop entries", or configuration files describing how a particular program is to be launched, how it appears in menus, etc. It is to the larger community's benefit that a unified standard be agreed upon by all parties such that interoperation between the two environments, and indeed any additional environments that implement the specification, becomes simpler.
These desktop entry files should have the extension
.desktop
. 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". Desktop entries
which describe how a directory is to be formatted/displayed
should be simply called .directory
.
Desktop entry files are encoded as lines of 8-bit characters separated by LF 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.
Key names must contain only the characters
A-Za-z0-9-
.
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.
The value types recognized are string
,
localestring
,
boolean
, and
numeric
.
Values of type string
may contain all ASCII
characters except for control characters.
Values of type localestring
are user displayable,
and are encoded in UTF-8.
Values of type boolean
must either be the string
true
or false
.
Values of type numeric
must be a valid floating
point number as recognized by the %f
specifier for
scanf
.
The escape sequences \s
, \n
,
\t
, \r
, and
\\
are supported for values of type
string
and localestring
, meaning
ASCII space, newline, tab, carriage return, and backslash, respectively.
Some keys can have multiple values. In such a case, the value of the key
is specified as a plural: for example, string(s)
. The
multiple values should be separated by a semicolon. Those keys which
have several values should have a semicolon as the trailing character.
Semicolons in these values need to be escaped using
\;
.
Keys with type localestring
may be postfixed by
[LOCALE
],
where LOCALE
is the locale type of the
entry. LOCALE
must be of the form
,
where
lang
_COUNTRY
.ENCODING
@MODIFIER
_
,
COUNTRY
.
,
and ENCODING
@
may be omitted. If a postfixed key occurs, the same
key must be also present without the postfix.
MODIFIER
When reading in the desktop entry file, the value of the key is
selected by matching the current POSIX locale for the
LC_MESSAGES
category against the
LOCALE
postfixes of all occurrences
of the key, with the
.
part
stripped.
ENCODING
The matching of is done as follows. If
LC_MESSAGES
is of the form
,
then it will match a key of the form
lang
_COUNTRY
.ENCODING
@MODIFIER
.
If such a key does not exist, it will attempt to match
lang
_COUNTRY
@MODIFIER
followed by
lang
_COUNTRY
.
Then, a match against lang
@MODIFIER
lang
by itself
will be attempted. Finally, if no matching key is found the
required key without a locale specified is used. The encoding
from the LC_MESSAGES
value is ignored
when matching.
If LC_MESSAGES
does not have a MODIFIER
field, then no key with a modifier will be matched. Similarly, if
LC_MESSAGES
does not have a COUNTRY
field, then no key with a country specified will be matched. If
LC_MESSAGES
just has a lang
field, then
it will do a straight match to a key with a similar value. The
following table lists possible matches of various LC_MESSAGES
values in
the order in which they are matched. Note that the
ENCODING
field isn't shown.
Table 1. Locale Matching
LC_MESSAGES value | Possible keys in order of matching |
---|---|
|
,
,
,
,
default value
|
|
,
lang ,
default value
|
|
,
lang ,
default value
|
lang |
lang ,
default value
|
For example, if the current value of the LC_MESSAGES
category
is sr_YU@Latn
and the desktop file includes:
Name=Foo Name[sr_YU]=... Name[sr@Latn]=... Name[sr]=...
then the value of the Name
keyed by sr_YU
is used.
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.
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.
| numeric | 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", should not be redundant with Name or
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 | File name of a binary on disk used to determine if the program is actually installed. If not, entry may not show in menus, etc. | string | NO | 1 |
Exec | Program to execute, possibly with arguments. | string | NO | 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_LAUNCH_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 | NO | 2 |
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 $PATH used by the desktop environment.
The name or path of the executable program may not contain the equal
sign ("="). Arguments are separated by a space.
Arguments may be quoted in whole. If an argument contains a reserved character the argument must be quoted. The rules for quoting of arguments is also applicable to the executable name or path of the executable program as provided.
Quoting must be done by enclosing the argument between double quotes and escaping the double quote character, backtick character ("`"), dollar sign ("$") 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.
If the standard is to be amended with a new {key,value}
pair which
should be applicable to all supporting parties, a group discussion
will take place. This is the preferred method for introducing
changes. If one particular party wishes to add a field for personal
use, they should prefix the key with the string X-
,
e.g. PRODUCT
X-NewDesktop-Foo
, following the precedent set by other IETF and RFC
standards.
Alternatively, fields can be placed in their own group, where they may
then have arbitrary key names. If this is the case, the group should
follow the scheme outlined above,
i.e. [X-
or
something similar. These steps will avoid namespace clashes between
different yet similar environments.
PRODUCT
GROUPNAME
]
[Desktop Entry] Version=1.0 Type=Application Name=Foo Viewer Comment=The best viewer for Foo objects available! TryExec=fooview Exec=fooview %F Icon=fooview.png MimeType=image/x-foo; X-KDE-Library=libfooview X-KDE-FactoryName=fooviewfactory X-KDE-ServiceType=FooService
For historical reasons KDE is using some KDE-specific extensions
that are currently not prefixed by a X-KDE-
prefix.
KDE specific keys: ServiceTypes
,
DocPath
, Keywords
,
InitialPreference
KDE specific types: ServiceType
,
Service
and FSDevice
KDE uses the following additional keys for desktop entries of the
FSDevice
type.
Table B.1. FSDevice Specific Keys
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.
Legacy-Mixed
Encoding (Deprecated)
The Legacy-Mixed
encoding corresponds to the
traditional encoding of desktop files in older versions of the GNOME and
KDE desktop files. In this encoding, the encoding of each
localestring
key is determined by the locale tag for
that key, if any, instead of being UTF-8. For keys without a locale tag,
the value must contain only ASCII characters.
If the file specifies an unsupported encoding, the implementation should either ignore the file, or, if the user has requested a direct operation on the file (such as opening it for editing), display an appropriate error indication to the user.
In the absence of an Encoding
key, the implementation may choose
to autodetect the encoding of the file by using such factors
as:
The location of the file on the file system
Whether the contents of the file are valid UTF-8
If the implementation does not perform such auto-detection, it should
treat a file without an Encoding
key in the same way as a file with an
unsupported Encoding
key.
If the locale tag includes an .
part, then that determines
the encoding for the line. Otherwise, the encoding is determined
by the language, or
ENCODING
pair from the locale tag, according to the following table.
lang
_COUNTRY
Encoding | Aliases | Tags |
---|---|---|
ARMSCII-8 (*) | hy | |
BIG5 | zh_TW | |
CP1251 | be bg | |
EUC-CN | GB2312 | zh_CN |
EUC-JP | ja | |
EUC-KR | ko | |
GEORGIAN-ACADEMY (*) | ||
GEORGIAN-PS (*) | ka | |
ISO-8859-1 | br ca da de en es eu fi fr gl it nl no pt sv wa | |
ISO-8859-2 | cs hr hu pl ro sk sl sq sr | |
ISO-8859-3 | eo | |
ISO-8859-5 | mk sp | |
ISO-8859-7 | el | |
ISO-8859-9 | tr | |
ISO-8859-13 | lt lv mi | |
ISO-8859-14 | cy ga | |
ISO-8859-15 | et | |
KOI8-R | ru | |
KOI8-U | uk | |
TCVN-5712 (*) | TCVN | vi |
TIS-620 | th | |
VISCII |
The name given here is listed here is typically the
canonical name for the encoding in the GNU C Library's
iconv
facility. Encodings marked with (*) are not
currently supported by the GNU C Library; for this reason,
implementations may choose to ignore lines in desktop
files that resolve to this encoding. Desktop files with
these encodings are currently rare or non-existent.
Other names for the encoding found in existing desktop files.
Language tags for which this is the default encoding.
This table above covers all tags and encodings that are known to
be currently in use. Implementors may choose to support
encodings not in the above set. For tags without defaults listed
in the above table, desktop file creators must specify the
.
part of the locale tag.
ENCODING
Matching the .
part of the locale tag against a locale
name or alias should be done by stripping all punctuation
characters from both the tag and the name or alias, converting
both name and alias to lowercase, and comparing the result.
This is necessary because, for example, ENCODING
Big5
is frequently
found instead of BIG5
and georgianacademy
instead of
GEORGIAN-ACADEMY
. Desktop files creators should, however, use
the name as it appears in the "Encoding" column above.