# Desktop Entry Specification

Version 1.0
6 Feb 2007
Preston Brown

    	    pbrown@kde.org

Jonathan Blandford

    	    jrb@redhat.com

Owen Taylor

    	    otaylor@gtk.org

Vincent Untz

    	    vuntz@gnome.org

Waldo Bastian

    	    waldo.bastian@intel.com

## Introduction

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.

## Basic format of the file

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.

### Comments

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.

### Group headers

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

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.

## Possible value types

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 `\;`.

## Localized values for keys

Keys with type `localestring` may be postfixed by [LOCALE], where LOCALE is the locale type of the entry. LOCALE must be of the form `lang_COUNTRY.ENCODING@MODIFIER`, where `_COUNTRY`, `.ENCODING`, and `@MODIFIER` may be omitted. If a postfixed key occurs, the same key must be also present without the postfix.

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 `.ENCODING` part stripped.

The matching of is done as follows. If `LC_MESSAGES` is of the form `lang_COUNTRY.ENCODING@MODIFIER`, then it will match a key of the form `lang_COUNTRY@MODIFIER`. If such a key does not exist, it will attempt to match `lang_COUNTRY` followed by `lang@MODIFIER`. Then, a match against 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.

Locale Matching

`LC_MESSAGES` value | Possible keys in order of matching
--- | ---
`lang_COUNTRY@MODIFIER` | `lang_COUNTRY@MODIFIER`, `lang_COUNTRY`, `lang@MODIFIER`, `lang`, default value
`lang_COUNTRY` | `lang_COUNTRY`, lang, default value
`lang@MODIFIER` | `lang@MODIFIER`, 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.

## Recognized desktop entry keys

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]`.

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

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.

## Registering MIME Types

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.

## Extending the format

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-PRODUCT`, e.g. `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-PRODUCT GROUPNAME]` or something similar. These steps will avoid namespace clashes between different yet similar environments.

## Example Desktop Entry File

    [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

## Currently reserved for use within KDE

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.

FSDevice Specific Keys

Key | Description | Value Type
--- | --- | ---
`Dev` | The device to mount. | string
`FSType` | The type of file system to try to mount. | string
`MountPoint` | The mount point of the device in question. | string
`ReadOnly` | Specifies whether or not the device is read only. | boolean
`UnmountIcon` | Icon to display when device is not mounted. Mounted devices display icon from the `Icon` key. `UnmountIcon`s may be localized with the `UnmountIcon[xx]=` syntax. | string

## Deprecated Items

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 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.

## The `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 `.ENCODING` part, then that determines the encoding for the line. Otherwise, the encoding is determined by the language, or `lang_COUNTRY` pair from the locale tag, according to the following table.

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 |  |

Encoding

  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.

Aliases

  Other names for the encoding found in existing desktop files.

Tags

  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 `.ENCODING` part of the locale tag.

Matching the `.ENCODING` 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, `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.