Linux has a hierarchical filing system that contains all the data files, programs, commands and special files that allow access to the physical computer system. The files are usually grouped into directories and subdirectories. The file system starts with a root directory and divides it into subdirectories. At each level, there can be further subdirectories that continue the file system onto further levels. There can also be files that contain data. A directory can contain both file types, although if no more directories are present, the file system will stop at that level for that path. A file name describes its location in the hierarchy by a combination of the path taken to locate it, starting at the top and working down. The splitting of the file structure makes it look like that of a tree and branches, where the trunk is represented by the root directory and branches by the subdirectories. Not surprisingly, this type of structure is frequently referred to as a tree structure. If turned upside down, it resembles a tree by starting at a single root directory the trunk and branching out.

The full name, or path name, for the file steve located at the bottom of the tree would be :/etc/usr/steve.: The / character at the beginning is the symbol used for the starting point and is known as root or the root directory. Subsequent use within the path name indicates that the preceding file name is a...