Pathname

A path name (also path ) is a character string that designates a file , a directory or, depending on the platform , other resources on a computer system , for example device files under Unix .

construction

Depending on the operating system , a path name consists of the following elements:

• a drive or volume label
• a list of directories or (sub) directories
• a filename

Almost all modern operating systems are designed to manage data (and thus files and directories) on multiple physical data carriers . Different approaches are used to address the data:

• Under Windows, for example, a path is preceded by an identification letter for the corresponding drive in which the data carrier is located.

Example of a path name under Windows: C:\privat\testdata\beispiel.txt

Here designates Cthe drive on which the file is located. In the top level of the file tree on this hard drive there is a directory privat, including one with a name testdata, and the file beispiel.txtcan be found there.

• Under Unix and Unix derivatives (e.g. Linux , NetBSD ) there is a “ root directory ”, from which addressing is purely directory-oriented. The root directory is usually on the data carrier from which the system is started. The operating system supports the integration of other available media then managing mount points , English mount points .

Example of a file name under Unix: /home/benutzer/beispieldatei

There is a directory in the root directory home, underneath benutzer, and there is beispieldatei.

The Unix path alone does not indicate which physical data carrier beispieldateiis on.

Absolute and relative path names

From the operating system perspective, a path name is only unambiguous if it is fully specified as described above. In order to simplify operation and program development, it is possible on most systems to work with so-called relative path names . Individual components of a path name are omitted, e.g. B. the drive specification or part of the preceding directory list.

Examples of relative path names:

• Windows: subdir\testfileor .\autoexec.bator..\daten\tabelle1.xls
• Unix: ../lib/libXYZ.a

The operating system manages the current drive (Windows / Apple only) and the current directory as reference points for relative path names for each running program. Incomplete, "relative" path information is then interpreted based on the current values.

Example (Windows):

• Current drive is C:
• Current directory is \privat\texte

An access to the relative path ..\daten\tabelle1.xlsis then C:\privat\texteinterpreted as starting from C:\privat\texte\..\daten\tabelle1.xls. The character string ..means a change to the higher-level directory. The resolved, simplified path name is then C:\privat\daten\tabelle1.xls. You can also call .\text1.txtthe path in this example C:\privat\texte\text1.txt, as it .always stands for the current directory.

Instead of the drive letter, it has become common today to specify the names in UNC format and, instead of the drive letter, also to specify the server name in Windows systems. See also Uniform Naming Convention .

Standard path

Depending on the type and purpose of the files to be saved, they are stored in certain places within hierarchically structured directory trees by default. See, for example, initialization file # location .