Editing Symbolic link (section)

==Variable symbolic links==
Symbolic links may be implemented in a context-dependent or variable fashion, such that the link points to varying targets depending on a configuration parameter, run-time parameter, or other instantaneous condition.

A ''variable'' or ''variant symbolic link'' is a symbolic link that has a variable name embedded in it. This allows some flexibility in filesystem order that is not possible with a standard symbolic link. Variables embedded in a symbolic link may include user and environment specific information.

[[Operating system]]s that make use of variant symbolic links include [[NetBSD]], [[DragonFly BSD]], [[Domain/OS]].<ref>{{Man|7|symlink|NetBSD}}: magic symlinks.</ref><ref>{{cite web|url=https://wiki.freebsd.org/200808DevSummit?action=AttachFile&do=get&target=variant-symlinks-for-freebsd.pdf |title=Variant symbolic links for FreeBSD |date=2008 |author=Brooks Davis}}</ref><ref name=":0" />
[[Tru64]] uses a ''context dependent symbolic link'' where the context is the cluster member number.

[[Pyramid Technology]]'s OSx operating system implemented ''conditional symbolic links'' which pointed to different locations depending on which [[Universe (Unix)|universe]] a program was running in.  The universes supported were AT&Ts's [[UNIX System V|SysV.3]] and the [[Berkeley Software Distribution]] (BSD 4.3). For example: if the [[ps (Unix)|ps]] command was run in the ''att'' universe, then the symbolic link for the directory ''/bin'' would point to ''/.attbin'' and the program ''/.attbin/ps'' would be executed. Whereas if the ps command was run in the ''ucb'' universe, then ''/bin'' would point to ''/.ucbbin'' and ''/.ucbbin/ps'' would be executed. Similar Conditional Symbolic Links were also created for other directories such as ''/lib'', ''/usr/lib'', ''/usr/include''.<ref>{{cite web|date=2016|website=LWN|title=A case for variant symlinks|url=https://lwn.net/Articles/680705/|author=Neil Brown}}</ref>