5.2 Directory Paths
5.2.1 Pathnames
The understanding of pathnames is critical to understanding file systems and is fundamental to understanding UNIX or any other operating system.  A pathname uniquely identifies a particular file or directory by specifying its location. Pathnames are similar to a road map or a set of directions that tells you how to get from one place in the directory hierarchy to another. For instance, if you were giving someone from another country directions on how to get to you, you would have to specify where you live. The directories in a file system can be compared to a country, state and city, etc. If the earth were like a hard disk with a file system, we would consider it the root of the file system. If we wanted to identify the location of a guy named Brad to tell someone where he lives, we would specify the pathname until we got to Brad. We would use a fully qualified pathname so there would be no doubt that we are talking about Brad of planet earth and not some other planet.

Figure shows the hierarchical relationship between the root directory and the coffees subdirectory. The set of directories you must go through from the root directory is the path name from the root directory through several intermediate subdirectories to the coffees subdirectory. Every file and directory in the file system has a pathname.