Symbolic Link

In computing, a symbolic link (also symlink or soft link) is a special type of file that contains a reference to another file or directory in the form of an absolute or relative path and that affects pathname resolution. Symbolic links were already present by 1978 in mini-computer operating systems from DEC and Data General's RDOS. Today they are supported by the POSIX operating-system standard, most Unix-like operating systems such as FreeBSD, GNU/Linux, and Mac OS X, and also Windows operating systems such as Windows Vista, Windows 7 and to some degree in Windows 2000 and Windows XP in the form of Shortcut files.

Symbolic links operate transparently for most operations: programs that read or write to files named by a symbolic link will behave as if operating directly on the target file. However, programs that need to handle symbolic links specially (e.g., backup utilities) may identify and manipulate them directly.

A symbolic link contains a text string that is automatically interpreted and followed by the operating system as a path to another file or directory. This other file or directory is called the "target". The symbolic link is a second file that exists independently of its target. If a symbolic link is deleted, its target remains unaffected. If a symbolic link points to a target, and sometime later that target is moved, renamed or deleted, the symbolic link is not automatically updated or deleted, but continues to exist and still points to the old target, now a non-existing location or file. Symbolic links pointing to moved or non-existing targets are sometimes called broken, orphaned, dead, or dangling.

Symbolic links are different from hard links. Hard links do not link paths on different volumes or file systems, whereas symbolic links may point to any file or directory irrespective of the volumes on which the link and target reside. Hard links always refer to an existing file, whereas symbolic links may contain an arbitrary path that does not point to anything.

Some Unix as well as Linux distributions use symbolic links extensively in an effort to reorder the file system hierarchy. This is accomplished with several mechanisms, such as variant and context-dependent symbolic links. This offers the opportunity to create a more intuitive or application-specific directory tree and to reorganize the system without having to redesign the core set of system functions and utilities .

Read more about Symbolic LinkPOSIX and Unix-like Operating Systems, Amiga, OS/2, Variable Symbolic Links

Other articles related to "symbolic link, symbolic links, link":

Unix File Types - Symbolic Link
... A symbolic link is a reference to another file ... A symbolic link is marked with an l (lower case L) as the first letter of the mode string, e.g ...
Softlink - 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 ... A variable or variant symbolic link is a symbolic link that has a variable name embedded in it ... order that is not possible with a standard symbolic link ...
Ln (Unix) - Usage - Symbolic Link Creation and Deletion
... The following shows the creation of a symbolic link slink.txt $ ln -s data.txt slink.txt $ ls -li 969768 -rw-r--r-- 1 alex alex 10 Dec 0911 ... data.txt 969817 ... The information stored in data.txt is accessible through the slink.txt $ file slink.txt slink.txt symbolic link to `data.txt' $ cat slink.txt some data If we delete the text file data.txt, slink.txt. 1 alex alex 8 Dec 0911 ... slink.txt -> data.txt $ file slink.txt slink.txt broken symbolic link to `data.txt' $ cat slink.txt cat slink.txt No such file or directory ...
Softlink - Microsoft Windows - Overview
... Property/Action Symbolic link Junction Hard link When symbolic link/junction/hard link is deleted.. ... reference counter is decremented when it reaches 0, the target is deleted When target is moved symbolic link becomes invalid junction becomes invalid hard link remains valid Relative path allowed ...
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 ... A variable or variant symbolic link is a symbolic link that has a variable name embedded in it ... in filesystem order that is not possible with a standard symbolic link ...

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