添加链接
link管理
链接快照平台
  • 输入网页链接,自动生成快照
  • 标签化管理网页链接

Will Thompson



Version 1.5

2020-04-27


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 extension should be a valid D-Bus well-known name . This means that it is a sequence of non-empty elements separated by dots (U+002E FULL STOP), none of which starts with a digit, and each of which contains only characters from the set [A-Za-z0-9-_] : ASCII letters, digits, dash (U+002D HYPHEN-MINUS) and underscore (U+005F LOW LINE). The name of the desktop entry should follow the "reverse DNS" convention: it should start with a reversed DNS domain name controlled by the author of the application, in lower case. The domain name should be followed by the name of the application, which is conventionally written with words run together and initial capital letters (CamelCase). For example, if the owner of example.org writes "Foo Viewer", they might choose the name org.example.FooViewer , resulting in a file named org.example.FooViewer.desktop . Well-known names containing the dash are allowed but not recommended, because the dash is not allowed in some related uses of reversed DNS names, such as D-Bus object paths and interface names, and Flatpak app IDs. If the author's domain name contains a dash, replacing it with an underscore is recommended: this cannot cause ambiguity, because underscores are not allowed in DNS domain names. If the author's domain name contains a label starting with a digit, (which is not allowed in D-Bus well-known names), prepending an underscore to that element of the desktop entry name is recommended. For example, 7-zip.org might release an application named org._7_zip.Archiver .

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.

The value types recognized are string , localestring , iconstring , 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 iconstring are the names of icons; these may be absolute paths, or symbolic names for icons located using the algorithm described in the Icon Theme Specification . Such values are not 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 in the C locale. The escape sequences \s , \n , \t , \r , and \\ are supported for values of type string , localestring and iconstring , 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 and the value of the key may be optionally terminated by a semicolon. Trailing empty strings must always be terminated with a semicolon. Semicolons in these values need to be escaped using \; .

Keys with type localestring and iconstring 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 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.

Table 1. 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 , 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. Although icon names of type iconstring are localizable, they are not human-readable strings, so should typically not be handled by translation tools. Most applications are not expected to localize their icons; exceptions might include icons containing text or culture-specific symbology.

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 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 1.5 . 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. iconstring NO 1-3
Hidden Hidden should have been called Deleted . It means the user deleted (at their 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 desktop environments that should display/not display a given desktop entry. By default, a desktop file should be shown, unless an OnlyShowIn key is present, in which case, the default is for the file not to be shown. If $XDG_CURRENT_DESKTOP is set then it contains a colon-separated list of strings. In order, each string is considered. If a matching entry is found in OnlyShowIn then the desktop file is shown. If an entry is found in NotShowIn then the desktop file is not shown. If none of the strings match then the default action is taken (as above). $XDG_CURRENT_DESKTOP should have been set by the login manager, according to the value of the DesktopNames found in the session file. The entry in the session file has multiple values separated in the usual way: with a semicolon. The same desktop name may not appear in both OnlyShowIn and NotShowIn of a group. string(s) NO 1-3
DBusActivatable A boolean value specifying if D-Bus activation is supported for this application. If this key is missing, the default value is false . If the value is true then implementations should ignore the Exec key and send a D-Bus message to launch the application. See D-Bus Activation for more information on how this works. Applications should still include Exec= lines in their desktop files for compatibility with implementations that do not understand the DBusActivatable key. boolean NO
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. See the Exec key for details on how this key works. The Exec key is required if DBusActivatable is not set to true . Even if DBusActivatable is true , Exec should be specified for compatibility with implementations that do not understand DBusActivatable . 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
Actions Identifiers for application actions. This can be used to tell the application to make a specific action, different from the default behavior. The Application actions section describes how actions work. string(s) 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
Implements A list of interfaces that this application implements. By default, a desktop file implements no interfaces. See Interfaces for more information on how this works. string(s) NO
Keywords A list of strings which may be used in addition to other metadata to describe this entry. This can be useful e.g. to facilitate searching through entries. The values are not meant for display, and should not be redundant with the values of Name or GenericName . localestring(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
PrefersNonDefaultGPU If true, the application prefers to be run on a more powerful discrete GPU if available, which we describe as “a GPU other than the default one” in this spec to avoid the need to define what a discrete GPU is and in which cases it might be considered more powerful than the default GPU. This key is only a hint and support might not be present depending on the implementation. boolean NO 1
SingleMainWindow If true, the application has a single main window, and does not support having an additional one opened. This key is used to signal to the implementation to avoid offering a UI to launch another window of the app. This key is only a hint and support might not be present depending on the implementation. boolean NO 1

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 (including the path), 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. 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. A single URL. Local files may either be passed as file: URLs or as file path. 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. Deprecated. Deprecated. Deprecated. Deprecated. 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. The translated name of the application as listed in the appropriate Name key in the desktop entry. 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. Deprecated. 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.

D-Bus Activation

Applications that support being launched by D-Bus must implement the following interface (given in D-Bus introspection XML format): <interface name='org.freedesktop.Application'> <method name='Activate'> <arg type='a{sv}' name='platform_data' direction='in'/> </method> <method name='Open'> <arg type='as' name='uris' direction='in'/> <arg type='a{sv}' name='platform_data' direction='in'/> </method> <method name='ActivateAction'> <arg type='s' name='action_name' direction='in'/> <arg type='av' name='parameter' direction='in'/> <arg type='a{sv}' name='platform_data' direction='in'/> </method> </interface> The application must name its desktop file in accordance with the naming recommendations in the introduction section (e.g. the filename must be like org.example.FooViewer.desktop ). The application must have a D-Bus service activatable at the well-known name that is equal to the desktop file name with the .desktop portion removed (for our example, org.example.FooViewer ). The above interface must be implemented at an object path determined as follows: starting with the well-known D-Bus name of the application, change all dots to slashes and prefix a slash. If a dash (' - ') is found, convert it to an underscore (' _ '). For our example, this is /org/example/FooViewer . The Activate method is called when the application is started without files to open. The Open method is called when the application is started with files. The array of strings is an array of URIs, in UTF-8. The ActivateAction method is called when Desktop Actions are activated. The action-name parameter is the name of the action. All methods take a platform-data argument that is used in a similar way to how environment variables might be used. Current fields described by the specification are: desktop-startup-id : This should be a string of the same value as would be stored in the DESKTOP_STARTUP_ID environment variable, as specified by the Startup Notification Protocol Specification . activation-token : This should be a string of the same value as would be stored in the XDG_ACTIVATION_TOKEN environment variable, as specified by the XDG Activation protocol for Wayland.

The Implements key can be used to declare one or more interfaces that a desktop file implements. Each interface name must follow the rules used for D-Bus interface names, but other than that, they have no particular meaning. For instance, listing an interface here does not necessarily mean that this application implements that D-Bus interface or even that such a D-Bus interface exists. It is entirely up to the entity who defined a particular interface to define what it means to implement it. Although it is entirely up to the designer of the interface to decide what a given interface name means, here are some recommended "best practices": interfaces should require that application is DBusActivatable, including the requirement that the application's desktop file is named using the D-Bus "reverse DNS" convention the interface name should correspond to a D-Bus interface that the application exports on the same object path as it exports the org.freedesktop.Application interface if the interface wishes to allow for details about the implementation, it should do so by specifying that implementers add a group in their desktop file with the same name as the interface (eg: "[org.freedesktop.ImageAcquire]") Recommendations notwithstanding, interfaces could specify almost any imaginable requirement including such (ridiculous) things as "when launched via the Exec line, the application is expected to present a window with the _FOO_IDENTIFIER property set, at which point an X client message will be sent to that window". Another example is "all implementations of this interface are expected to be marked NoDisplay and, on launch, will present no windows and will delete all of the user's files without confirmation". Interface definers should take care to keep issues of backward and forward compatibility in mind when designing their interfaces.

Desktop entries of type Application can include one or more actions. An action represents an additional way to invoke the application. Application launchers should expose them to the user (for example, as a submenu) within the context of the application. This is used to build so called "Quicklists" or "Jumplists".

Each action is identified by a string, following the same format as key names (see the section called “Entries” ). Each identifier is associated with an action group that must be present in the .desktop file. The action group is a group named Desktop Action %s , where %s is the action identifier. It is not valid to have an action group for an action identifier not mentioned in the Actions key. Such an action group must be ignored by implementors.

C. 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 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.

D. 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 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