File association

A file association associates a file with an application capable of opening that file. More commonly, a file association associates a class of files (as determined by their filename extension, such as .txt) 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 fileA picture, for example, may be associated with these verbs so that "open" opens the picture in an image viewer, "edit" opens up an 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. 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 systems, beginning with Windows 95 supports file extension-based associations. Associations are stored in registry 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 assoc command. [ [http://technet.microsoft.com/en-us/library/bb490865.aspx Microsoft TechNet Assoc article] ]

Linux

Linux-based GUIs, such as KDE and GNOME, support MIME type-based associations. For example, the MIME type text/plain might be associated with a text editor.

Mac OS

Classic Mac OS used type codes and creator codes to associate each file with its corresponding application, regardless of file extension. The more recent Mac OS X also supports file extension-based associations.

OS/2

ee also

*File format
*Filename extension

References

External links

* [http://msdn2.microsoft.com/en-us/library/bb776883.aspx Verbs and File Associations in Microsoft Windows]
* [http://docs.kde.org/userguide/file-associations.html File Associations in KDE]