Basic UNIX

• UNIX is an operating system designed over 20 years ago by Ken Thompson and Dennis Ritchie at AT&T Labs. UNIX was to be a tool for programmers, not a commercial system. It was distributed freely to universities, and over time, thousands of researchers and hackers added features and corrected bugs, helping UNIX evolve into a stable system. It is now the most used operating system on the Internet.

• To use UNIX you need a login account, that is, you need to be able to login to a UNIX machine. mail.utexas.edu, for example, is setup so that you can't login, you can only use it to run "client" programs on other machines, e.g., Eudora running on your PC as a mail client. For this lab, you need a login account, preferably on the GSLIS cluster.

• Your home directory is preset for you, so that when you login, you will find yourself in your own area on the machine's file directory system.

  Basic unix commands
  We will now practice very basic unix commands. Their functionality is similar to what you find in basic DOS commands (dir, cd, copy, etc.) and the directory system has basically the same hierarchical structure. See also Todino et.al.; or Appendix D in the Krol book; or consult the UNIX Reference Desk for additional help.

• Remember: unix is case sensitive! FileA is not the same file as filea. In general, try to use lowercase only.

• ls : used to list the contents of a directory. Simply type in ls and press enter or return. You should see a few file names.

• ls -l : optional arguments for the ls command (and for any command on unix) are preceded by a dash, "-". The optional l shows all file details (make sure you understand what each part of the description means.)

• ls -a : the optional a in the ls shows all files, including the "." files (try it out. What kind of files are these?)

• If you wish to display the contents of a file, use the more command. This is a very useful tool, it lets you display the contents of a file one screenful at a time. Try it on one of your files, for example:

  	more .login

• man : helps you find out more about a command. Look at the man pages for ls by typing:

  	man ls

• Finally, here are some additional commands you will find useful Please review these at your own pace after today's Lab session.