File system

• Files are orgnized in hierarchical way. The very top directory is called the system root directory (referred to as /). From there, subdirectories comprise the rest of the system. Each level of hierarchy is delimited by '/'.

  

  If you want to know more about the standard UNIX file system hierarchy, the following command will give you additional info:

     man hier
  

• There are two ways to reference a file or directory in UNIX.
  • One way is called an Absolute Path. That is a reference to a file from the system root directory. An example would be /home/cowboyNeal/whisky.txt. This is the Absolute Path name for the file which is a text file of good whisky list. You can use this reference no matter where you are in the file structure. Absolute Paths always begin with a slash (/). To see a file,

       more /home/cowboyNeal/whisky.txt
    

  • The second way to reference files is called the Relative Path name. The relative path name is a reference to a file or directory based on where you are in the file system. If, for instance, you are in the /home directory and want to read a file in the /home/bubba directory called data.txt, you could type

       more bubba/data.txt
    

    If you are in the /home/cowboyNeal directory, then you can read the same file by

       more ../bubba/data.txt
    

• There are several special directories.
  

  ..	means one directory above
  .	means current directory
  ~	means home directory (e.g. /home/cowboyNeal for the user cowboyNeal).