Sunday, April 26, 2009

Introduction to Unix

This is a quick intro to Unix aimed at beginners who do not have any previous experience using Unix System. It will not attempt to be a rough guide through all the steps neccessary to use the system.
The following information is intended as a general description of Unix and is not intended as complete information about any aspect of the system. There are many useful sites provide very helpful information for users of the UNIX operating system; visit the University of Edinburgh home site, the place where many helpfull files could be found (use FTP to explore the full directory:, and The UNIX System Home Page, or here a Complete Unix Tutorial, and many other sites you can find on the net... But if you are not sure which one you should choose I think the best thing you should do is just to download a full Unix help files which was writen by Gavin Inglis as Unixhelp maintainer, and here is the link to download. The package consists of all tasks, commands, concepts and informations about some of the general purpose utilities that are provided as standard by UNIX.


  1. Unix is a computer operating system.
  2. Unix was first developed in the 1960s.
  3. It's a multi-user, multi-tasking operating system. Multiple users may have multiple tasks running simultaneously. This is very different than PC operating systems.
  4. knowledge of UNIX is required for operations which aren't covered by a graphical program, or for when there is no windows interface available, for example, in a telnet session.

II. Unix Components

  1. Kernel
    The core of the UNIX system. Loaded at system start up (boot).
    The kernel of UNIX is the hub of the operating system: it allocates time and memory to programs and handles the filestore and communications in response to system calls.

  2. Shell
    The shell is a command line interpreter (CLI).
    The shell acts as an interface between the user and the kernel. When a user logs in, the login program checks the username and password, and then starts another program called the shell. it takes each command and passes it to the operating system kernel to be acted upon. It then displays the results of this operation on your screen.
    The most commonly available shells are: Bourne shell (sh), Bourne Again Shell (bash), C shell (csh), TC Shell (tcsh), and Korn shell (ksh).
    Each shell also includes its own programming language. Command files, called "shell scripts" are used to accomplish a series of tasks.

  3. Utilities and Programs
    UNIX provides several hundred programs, often referred to as commands. Below are the most available programs that you will find on Unix :

    1. Program development tools
    2. Text editors
    3. File manipulation utilities
    4. and File transfer utilities

III. Unix Commands

  1. Unix provides hundreds of useful commands for all sorts of purposes.
  2. The Unix command is the name of a built-in shell command, a system utility or an application program.
  3. Almost everything about Unix is case-sensitive including the commands, filename, directory ect.
  4. Not all of these are actually part of UNIX itself, and you may not find them on all UNIX machines. But they can all be used on turing in essentially the same way, by typing the command and hitting return.
  5. The basic form of any Unix command is:

      command_name options argument(s)

    For example :

      rm -r dir.1 (to remove directory dir.1 and it's contents)

  6. Note : Some of these commands are different on non-Solaris machines.

  7. Read the Basic Unix Commands to get started with the basical types of them.

IV. Starting Unix

  1. Before you can begin to use the system you will need to have a valid username and a password.
  2. When you connect to a UNIX computer remotely or when you log in locally using a text-only terminal, you will see the prompt:

      login as:

  3. At this prompt, type in your username and press the enter/return, you should then be prompted for your password:

      login as: hamzah

    Note: Your password will not be displayed on the screen as you type it in.

    Read How to login to Unix if you need to learn more about starting unix using other applications such putty or FileZilla.


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