Directory path names

Each file and directory can be reached by a unique path, known as the path name, through the file system tree structure. The path name specifies the location of a directory or file within the file system.

The file system uses the following kinds of path names:

An absolute path name represents the complete name of a directory or file from the /(root) directory downward. Regardless of where you are working in the file system, you can always find a directory or file by specifying its absolute path name. Absolute path names start with a slash (/), the symbol representing the root directory. The path name /A/D/9 is the absolute path name for 9. The first slash (/) represents the /(root) directory, which is the starting place for the search. The remainder of the path name directs the search to A, then to D, and finally to 9.

Two files named 9 can exist because the absolute path names to the files give each file a unique name within the file system. The path names /A/D/9 and /C/E/G/9 specify two unique files named 9.

Unlike full path names, relative path names specify a directory or file based on the current working directory. For relative path names, you can use the notation dot dot (..) to move upward in the file system hierarchy. The dot dot (..) represents the parent directory. Because relative path names specify a path starting in the current directory, they do not begin with a slash (/). Relative path names are used to specify the name of a file in the current directory or the path name of a file or directory above or below the level of the current directory in the file system. If D is the current directory, the relative path name for accessing 10 is F/10. However, the absolute path name is always /A/D/F/10. Also, the relative path name for accessing 3 is ../../B/3.

You can also represent the name of the current directory by using the notation dot (.). The dot (.) notation is commonly used when running programs that read the current directory name.