Bash-Beginners-Guide

Bash Guide for Beginners
Table of Contents
Chapter 7. Conditional statements
7.2.4. Boolean operations................................................................................................................88
7.2.5. Using the exit statement and if..............................................................................................89
7.3. Using case statements.....................................................................................................................90
7.3.1. Simplified conditions............................................................................................................90
7.3.2. Initscript example..................................................................................................................92
7.4. Summary.........................................................................................................................................92
7.5. Exercises.........................................................................................................................................93
Chapter 8. Writing interactive scripts............................................................................................................94
8.1. Displaying user messages...............................................................................................................94
8.1.1. Interactive or not?..................................................................................................................94
8.1.2. Using the echo built-in command.........................................................................................94
8.2. Catching user input.........................................................................................................................97
8.2.1. Using the read built-in command..........................................................................................97
8.2.2. Prompting for user input........................................................................................................98
8.2.3. Redirection and file descriptors.............................................................................................99
8.2.4. File input and output............................................................................................................101
8.3. Summary.......................................................................................................................................106
8.4. Exercises.......................................................................................................................................106
Chapter 9. Repetitive tasks............................................................................................................................108
9.1. The for loop...................................................................................................................................108
9.1.1. How does it work?...............................................................................................................108
9.1.2. Examples.............................................................................................................................108
9.2. The while loop..............................................................................................................................109
9.2.1. What is it?............................................................................................................................109
9.2.2. Examples.............................................................................................................................110
9.3. The until loop................................................................................................................................112
9.3.1. What is it?............................................................................................................................112
9.3.2. Example...............................................................................................................................112
9.4. I/O redirection and loops..............................................................................................................113
9.4.1. Input redirection..................................................................................................................113
9.4.2. Output redirection................................................................................................................113
9.5. Break and continue.......................................................................................................................114
9.5.1. The break built-in................................................................................................................114
9.5.2. The continue built-in...........................................................................................................115
9.5.3. Examples.............................................................................................................................116
9.6. Making menus with the select built-in..........................................................................................117
9.6.1. General................................................................................................................................117
9.6.2. Submenus............................................................................................................................118
9.7. The shift built-in...........................................................................................................................118
9.7.1. What does it do?..................................................................................................................118
9.7.2. Examples.............................................................................................................................119
9.8. Summary.......................................................................................................................................120
9.9. Exercises.......................................................................................................................................120
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