AIX Shell Programming — A 2-Day Course

 Open Public Course Closed In-House Course

Synopsis

This course is designed to give delegates practical experience in developing and writing AIX shell scripts. Most of the built-in shell commands are introduced together with the main program control structures. This course is not suitable for C shell programmers.

The delegates will practise: -

• Writing simple scripts to enhance basic command output
• Using the various shell quoting mechanisms appropriately
• Manipulating shell variables and user-defined variables in scripts
• Implementing conditional execution facilities
• Using the shell's built-in loop constructs where appropriate
• Writing scripts to trap user interrupts
• Developing menu-driven shell scripts

Course Objectives

To provide the skills needed to develop and customise shell programs.

Suitable for

• Programmers, administrators and support personnel who need to understand existing shell scripts, automate procedures and write their own utilities.

Prerequisites

• The course assumes knowledge of the AIX Operating System to the level covered in the AIX Basics Course
• Some programming experience may also prove advantageous

Publicly scheduled dates, locations, and prices

Course Contents:

AIX Command Review

• Basic Unix commands
• General commands
• File and directory handling commands
• Filename generation characters
• I/O Redirection features
• Other commands

Getting Started

• What is a shell script?
• Development guidelines
• Creating and editing shell scripts
• Naming and storing shell scripts
• Executing shell scripts
• Exercise: Write a simple shell script

Using Variables

• Environment variables
• Local variables
• Assigning values to variables
• Assessing variable values
• Using quotes
• Delimiting variable names
• Echo control sequences
• Exercise: Add variables to a script

Integer Arithmetic

• Using the expr command
• Using the (( )) notation
• Exercise: Add integer arithmetic to a shell script

Handling Run Time Data

• The read command
• Command line arguments
• Exercise: Writing a generic shell script
• Exercise: Writing an interactive shell script

Condition Execution

• The if statement
• The test command
• Other test notations
• Default and substitute variables
• Exit status codes
• Exercise: Adding validation to previous scripts

Loop Constructs

• The while loop
• The until loop
• The for loop
• The while true and until false loops
• Loop control commands
• Exercise: Enhancing the previously written scripts
• Exercise: Writing a guess-the-number game

Multi-Branch Decisions

• The case statement
• Menu driven applications
• Exercise: Developing and writing a menu system

Functions

• What is a function?
• Syntax
• Examples
• Exercise: Add a function to a script

Interrupt Handling

• Interrupt signals
• Trapping interrupts
• Exercise: Adding traps to the menu script

Additional Features and Facilities

• The exec commands
• The includes notation
• More about loops
• Arrays
• Here Documents
• Exercise: Create a here script