Unix File System Unix File System Revised January 14, 2001. Press your browser's Reload or Refresh button to get the latest version. Files and directories A file is a piece of permanent storage in a computer. Files store documents, images, programs, etc.
Every file has a filename .
Since a directory is just a kind of file, a directory can list other directories. Unix uses a hierarchical directory structure where directories are organized into a tree . Each subdirectory lists its own subdirectories, etc., creating a branching structure as in this example . Every file can be identified by a unique absolute pathname formed by listing all the directories in order from root, ending with the filename. Relative pathnames and the working directory Absolute pathnames can be long and cumbersome to work with.