UNIX Pathnames

Pathnames specify where in the hierarchy a particular file is located. The root directory has a pathname of /. The pathname /tmp/a.out indicates that the file a.out resides in the directory tmp, which is located in the root directory /.

Pathnames may specify the complete path from the root directory, or they can be relative to the current directory. Suppose you are located in /tmp and wish to use the file /tmp/run1/a.out. You can specify the file with run1/a.out, or specify the complete pathname of /tmp/run1/a.out.