Linux: Bash Shell and Scripts

Get an introduction to Linux bash scripting. Learn how to read and write Linux bash scripts, complete with local variables, functions, loops, and coprocesses, and use sed and AWK.

Introduction

• Welcome
• What you should know
• Using the exercise files

1. Intro to Bash Scripting

• Exploring the Bash documentation
• Setting the script interpreter and permissions
• Time commands and set variables
• Bash startup
• Sourcing and aliasing with bash
• Displaying text with the echo command
• Challenges: Scripts with exported variables, sourcing, and echo
• Solutions: Scripts with exported variables, sourcing, and echo

2. Variables, Control Structures, and Arithmetic

• The typeset and declare commands for variables
• Looping with for/while sequences and reading input
• Defining functions and using return and exit
• Using file descriptors, file redirection, pipes, and here documents
• Control-flow case statements and if-then-else with the test command
• Using arithmetic operators
• Challenges: Using local variables in functions, loops, and arithmetic
• Solutions: Using local variables in functions, loops, and arithmetic

3. Using Filters and Parameter Expansion

• Defining filters and using head, tail, and wc
• Using sed and AWK for more powerful scripting
• Positional parameters and operators with braces
• Challenges: Looping, special variable operators, sed, and AWK
• Solutions: Looping, special variable operators, sed, and AWK

4. Advanced Bash

• Using the coproc command
• Debugging scripts with -x and -u options
• Signals and traps
• Using the eval and getopt commands
• Challenges: Debugging scripts using trap, eval, getopt, and coproc
• Solutions: Debugging scripts using trap, eval, getopt, and coproc

Conclusion

• Next steps