• ``Everything is a file''
• Where (and what) files ``really'' are (physical disks, network fileserver, CD, tape, modem, keyboard) is generally invisible to the user, same naming conventions are used.

• No / or null characters
• Any (reasonable) length, and (remember) case sensitive.
• Suggestion: restrict yourself to letters, digits, dot(.), underscore.
• Avoid shell metacharacters! And leading hyphens! And control-characters!
• Convention: dot-suffix tells type of file (which, rarely, programs will enforce):
  • thing.c - C source file
  • entity.f - Fortran source file
  • item.o - Binary object file
  • object.html - HTML source
• Files with a leading dot are ``invisible''.

• directories can contain files or subdirectories
• all files and directories descend from the "root" directory /
• each user has a home directory in the tree in which he or she can create files and subdirectories
• each Unix process has a ``current working directory''.
• location of files by ``paths'', either
  • absolute, directions from the root directory, begin with a /

    /vmunix
    /bin/ksh
    /user1/pas/bin/demo.setup
    

  • relative, directions from the current working directory, don't begin with a slash.

    bin
    bin/demo.setup
    ../misdev/abin/sutomisdev
    ../../vmunix
    

On to Filesystem Commands...