Pathname

A path, the general form of the name of a file or directory, specifies a unique location in a file system. A path points to a file system location by following the directory tree hierarchy expressed in a string of characters in which path components, separated by a delimiting character, represent each directory. The delimiting character is most commonly the slash ("/"), the backslash character ("\"), or colon (":"), though some operating systems may use a different delimiter. Paths are used extensively in computer science to represent the directory/file relationships common in modern operating systems, and are essential in the construction of Uniform Resource Locators (URLs). Resources can be represented by either absolute or relative paths.

Multics first introduced a hierarchical file system with directories (separated by ">") in the mid-1960s.

Around 1970, Unix introduced the slash character ("/") as its directory separator.

In 1981, the first version of Microsoft DOS was released. MS-DOS 1.0 did not support file directories. Also, a major portion of the utility commands packaged with MS-DOS 1.0 came from IBM and their command line syntax used the slash character as a 'switch' prefix. For example, dir /w runs the 'dir' command with the wide list format option.

This use of slash can still be found in the command interface under Windows. By contrast, Unix uses the dash ("-") character as a command line switch prefix.

When directory support was added to MS-DOS in version 2.0, "/" was kept as the switch prefix character for backwards compatibility. Microsoft chose the backslash character ("\") as a directory separator, which looks similar to the slash character.

An absolute or full path points to the same location in a file system, regardless of the current working directory. To do that, it must include the root directory.

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