Editing File association

In [[computing]], a '''file association''' associates a file with an [[application software|application]] capable of opening that file. More commonly, a file association associates a class of files (usually determined by their [[filename extension]], such as <code>[[.txt]]</code>) with a corresponding application (such as a [[text editor]]).

==Associations and verbs==
A single file extension may have several associations for performing various actions, also known as '''verbs'''. Some of the common verbs are:
* ''open'' to open a file
* ''edit'' to open a file for editing
* ''print'' to print a file
A [[digital image|picture]], for example, may be associated with these words so that ''open'' opens the picture in an [[image viewer]], ''edit'' opens up an [[graphics software|image editing]] program and ''print'' sends the picture to a printer.

==Implementations==
Most [[operating systems]] support file associations in some form or the other. For example, opening a file from a file manager usually invokes the ''open'' verb in order to open the file with its associated application. The "open" verb invokes the associated [[application program]], which reads the file or document and presents it to the user for viewing, and possibly for editing or other action. 

Additional actions such as ''print'' are usually accessed via a right-click [[context menu]]. A mechanism for modifying associations is also usually present. An example for this is the ''Open With'' option in the [[Windows Shell]].

===Microsoft Windows===
The [[Microsoft Windows]] series of [[operating system]]s, beginning with [[Windows 3.x]] supports file extension-based associations.<ref>{{Cite web|url=http://www.fandecheng.com/personal/interests/ewindows/windows3x/features.htm|title = Windows 3.x Features}}</ref> Associations are stored in [[Windows Registry|registry]]<ref>[http://msdn.microsoft.com/en-us/library/windows/desktop/ms724475(v=vs.85).aspx HKEY_CLASSES_ROOT Key]</ref> as sets of verbs for each file extension. Older versions supported ''open'' associations stored in [[WIN.INI]].
File associations can be displayed and edited using the <code>assoc</code> [[command (computing)|command]] and with the help of the <code>[[ftype]]</code> command it is possible to create association between file type and application which will open files of this type.<ref>[https://technet.microsoft.com/en-us/library/bb490865.aspx Microsoft TechNet Assoc article] on <code>assoc</code></ref><ref>[https://technet.microsoft.com/en-us/library/bb490912.aspx Microsoft TechNet Ftype article] on <code>ftype</code></ref>

The Windows shell invokes file association actions through [[Component Object Model|COM]], drag and drop, command line calls or through [[Dynamic Data Exchange]]. Advanced features of Microsoft Windows file associations included manually defining a new file extension with any number of associated actions, a primary ''default action'', showing extensions only for specific file types, customizing the file type icon and description and customizing associated [[MIME]] type and their handling (how to handle file types for files downloaded or directly opened from within the [[Internet Explorer]] browser). The ability to configure advanced file association functionality, however, was removed in [[Windows Vista]] and later operating systems.

===Linux===
[[Linux]]-based GUIs, such as [[KDE]] and [[GNOME]], support [[Internet media type|MIME type]]-based associations.{{cn|date=December 2024}} For example, the MIME type <code>text/plain</code> would be associated with a [[text editor]]. This association is generally accomplished through the [[freedesktop.org]] Shared MIME database (for determining the MIME type of a file) and the [[Desktop Entry specification]] (for determining which application to open the file with).<ref>{{cite web |title=Association between MIME types and applications |url=https://specifications.freedesktop.org/mime-apps-spec/latest/ |website=specifications.freedesktop.org |access-date=2 December 2024}}</ref>

===Mac OS===
The [[Classic Mac OS]] used [[type code]]s and [[creator code]]s to associate each file with its corresponding application, regardless of file extension. The more recent [[macOS]] also supports file extension–based associations.

Application bundles in macOS declare supported file types in their Info.plist file. For each of these specified types, a [[Uniform Type Identifier]] is given, along with a list of 'tags' which define how a file or data of this type could be identified. For example, the [[JPEG]] type is defined with a UTI of 'public.jpeg', and tagged with the extensions 'jpg' and 'jpeg', the [[MIME]] type 'image/jpeg' and the [[type code]] 'JPEG'.<ref>[https://developer.apple.com/mac/library/documentation/FileManagement/Conceptual/understanding_utis/understand_utis_conc/understand_utis_conc.html#//apple_ref/doc/uid/TP40001319-CH202-CHDHIJDE Mac OS X Reference Library - Uniform Type Identifier Concepts]</ref>

The operating system uses this information to generate a list of applications which are able to open each type. Within [[Finder (software)]] each file will be identified with a UTI and open with the default application for that type. The user may also select from a list of other applications which support the type.

Using this system, types are also associated with data for which there is no file name or the file extension is missing. This includes pasteboard data and data streaming over a protocol such as [[HTTP]] where a MIME type has been given.

==See also==
*[[File format]]
*[[Filename extension]]

==References==
{{Reflist}}

==Further reading==
{{refbegin}}
#{{Cite web
 |url = http://msdn.microsoft.com/en-us/library/ff521657(v=VS.85).aspx
 |title = Implementing a Custom File Format
 |work = [[Microsoft Developer Network]] Library
 |publisher = Microsoft Corporation
 |date = 9 November 2010
 |access-date = 5 December 2010
 }}
#{{Cite web
 |url = https://docs.kde.org/stable5/en/kde-workspace/kcontrol5/filetypes/index.html
 |title = File Associations
 |work = KDE Documentation
 |publisher = [[KDE]]
 |date = 11 November 2016
 |access-date = 30 May 2020
 }}
{{refend}}

{{Windows commands}}

{{DEFAULTSORT:File Association}}
[[Category:Metadata]]