04.Shell-scripting.pdf

Shell Scripting

Hamish Whittal

Shell Scripting

by Hamish Whittal

Published 2005-01-25 22:36:19

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Table of Contents

1. Tour de Shell Scripting ...........................................................................1

Introduction to the Course structure ....................................................1

Adage 1.0: ................................................................................1

What you will need ....................................................................1

What is Shell Scripting ..............................................................2

Introduction to info, man and the whatis database ................................4

info pages .................................................................................4

Man Pages ................................................................................9

The whatis Database ................................................................12

Revising some Basic Commands ......................................................13

The who command ..................................................................14

The w Command .....................................................................16

The "date" command ...............................................................17

The 'echo' command ................................................................20

File Commands .......................................................................23

System Commands ..................................................................29

stdin, stdout, stderr ..........................................................................33

stdin .......................................................................................34

stdout ......................................................................................34

Using stdin and stdout simultaneously .......................................37

Appending to a file ..................................................................37

stderr ......................................................................................38

stdout, stderr and using the ampersand (&) ................................40

Exercises: ................................................................................41

Unamed Pipes .........................................................................41

2. The Shell .............................................................................................45

Introduction ....................................................................................45

What is the login shell? ....................................................................46

Exercises .................................................................................48

The job of the shell ..........................................................................50

Command Interpreter ...............................................................50

Allows for variables to be set ....................................................51

I/O redirection .........................................................................51

Pipelines .................................................................................51

Customising your environment .................................................51

Conclusion: .............................................................................51

3. Regular Expressions .............................................................................53

Introduction ....................................................................................53

What are regular expressions? ..........................................................53

The fullstop .............................................................................54

Let's explore "sed" syntax ........................................................55

Square brackets ( [ ] ), the caret ( ^ ) and the dollar ( $ ) .............56

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