17-09-2012, 10:21 AM
Introduction to UNIX
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What is UNIX?
A computer operating system
A software development environment
Built in late '60s, early '70s by Ken Thompson
and Dennis Ritchie
Originally written in assembler, later rewritten in
C (allowing greater portability), a language
invented by Ritchie
UNIX Philosophy
Make each program do one thing well.
Reusable software tools: 1 tool = 1 function
Expect the output of every program to become the
input of another, yet unknown, program to
combine simple tools to perform complex tasks
Everything seen as a file
File System
"Files have places and processes have life"
Kaare Christian
All files are "flat": just a sequence of bytes
File system is hierarchical
Logging In
To log in to a Unix machine you can either:
sit at the console (the computer itself)
access via the net (using telnet, rsh, ssh, or
some other remote access client).
To access machines in ITD415, use
id415mxx.cs.unb.ca as hostname, where xx =
01-40
The system prompts you for your username
and password.
Usernames and passwords are case
sensitive!
Session Startup
Once you log in, your shell will be started
and it will display a prompt.
When the shell is started it looks in your
home directory for some customization
files.
You can change the shell prompt, your PATH,
and a bunch of other things by creating
customization files.