CS 497C – Introduction to UNIX Lecture 1: Getting Started Chin-Chih Chang

Objective and Preface This course is to learn the fundamentals of UNIX. This course introduces the concept of UNIX operating system and the essential commands of UNIX. UNIX was never designed for the world. There is a method to this madness. Many Internet applications are powered by UNIX.

The Operating System An operating system (sometimes abbreviated as “OS”) is a program that functions as a virtual machine (layer of software on top of bare hardware) and a resource manager (software that controls access to computer). It interacts with two agencies: applications and a command language interpreter. DOS, Windows, Mac OS, and UNIX are examples of the operating system.

The UNIX Operating System UNIX (sometimes spelled “Unix”) is an operating system that originated at Bell Labs in Ken Thompson and Dennis Ritchie are considered the inventors of UNIX. UNIX has evolved as a kind of large freeware product, with many extensions and new ideas provided in a variety of versions of UNIX by different companies, universities, and individuals.

Knowing Your Machine Unlike Windows, UNIX can be used by several users concurrently. You can access to such a multiuser system through a terminal or a workstation. A terminal consists of a monitor and a keyboard. A workstation has its own CPU, memory, and hard disk.

Knowing Your Keyboard Every key on your computer has a function in UNIX. Each character has its ASCII value. [Enter] / [Return] is used to terminate a line. [Backspace] corrects typing mistakes. [Ctrl] is used in combination with other keys to produce control characters. [Alt] combinations are used in emacs.

The System Administrator A system administrator is in charge of administration of the system. The system administrator is responsible for: –the entire setup, –user accounts allocation, –file systems maintenance, –backups, –disk space management, –other assignments. The administrator has a special user account; it is called root.

Logging In and Out Logging In login: remeo [Enter] password: Last login: Mon Aug 20 22:11:17 on tty2 $ The shell produces the prompt and accepts all your input from the keyboard. Logging Out $ [Ctrl-d] $logout[Enter] $exit[Enter] login:

Trying Out Some Commands passwd: changing your own password who: who are the users? who am i tty: know your terminal name echo $SHELL: know your shell echo $TERM: know your terminal type set: know your envirnoment

Two Important Observations UNIX commands are in lowercase The [Enter] key

When Things Go Wrong Backspacing doesn’t work – [Ctrl-h], [Del] A command has to be interrupted – [Ctrl-d], [Ctrl-c] [Delete] Killing a line – [Ctrl-u] Other Problems –Suspend a job – [Ctrl-z], resume a job – fg –Stop scrolling – [Ctrl-s], resume scrolling - [Ctrl-q] –Restore a terminal – stty sane –[Enter] – [Ctrl-j] or [Ctrl-m] –Close the program - q, quit, exit, or [Ctrl-d]

What’s Next More commands How It All Clicked Linux and GNU Inside UNIX Read Chapter 1.