Shell Scripting Study Guide¶

Introduction¶

This folder provides a systematic study of shell scripting as a programming discipline. Using Bash as the primary shell, it covers advanced techniques, real-world automation patterns, and professional best practices that go well beyond basic scripting.

Target audience: Learners who have completed the Linux topic (especially Lesson 09: Shell Scripting basics)

Learning Roadmap¶

[Foundation]              [Intermediate]             [Advanced]
    |                         |                          |
    v                         v                          v
Shell Basics/Env ------> Functions/Libs ---------> Portability/Best Practices
    |                         |                          |
    v                         v                          v
Parameter Expansion ----> I/O & Redirection ------> Testing
    |                         |
    v                         v                     [Projects]
Arrays & Data ----------> String/Regex ----------> Task Runner
    |                         |                          |
    v                         v                          v
Adv. Control Flow ------> Process/Error ----------> Deployment
                              |                          |
                              v                          v
                         Arg Parsing/CLI ---------> Monitoring Tool

Prerequisites¶

Linux basics and terminal familiarity
Linux/09_Shell_Scripting.md - variables, conditionals, loops, functions, arrays, debugging basics
Linux/04_Text_Processing.md - grep, sed, awk basics

File List¶

Foundation (Review + Beyond Basics)¶

File	Difficulty	Key Topics
01_Shell_Fundamentals.md	⭐	Shell types (bash/sh/zsh/dash), POSIX, login/non-login, profile/bashrc loading, exit codes
02_Parameter_Expansion.md	⭐⭐	String manipulation, ${var#}, ${var//}, substring, indirect refs, declare
03_Arrays_and_Data.md	⭐⭐	Associative arrays, stack/queue simulation, CSV parsing, config loading
04_Advanced_Control_Flow.md	⭐⭐	[[ ]] vs [ ] vs (( )), extglob, select menus, arithmetic with bc

Intermediate (Deep Techniques)¶

File	Difficulty	Key Topics
05_Functions_and_Libraries.md	⭐⭐	Return patterns, recursion, function libraries, namespacing, callbacks
06_IO_and_Redirection.md	⭐⭐⭐	File descriptors, here documents, process substitution, named pipes, pipe pitfalls
07_String_Processing.md	⭐⭐⭐	Built-in string ops, printf, tr/cut/paste/join, jq/yq for JSON/YAML
08_Regex_in_Bash.md	⭐⭐⭐	=~ operator, BASH_REMATCH, extended regex, glob vs regex, practical validation
09_Process_Management.md	⭐⭐⭐	Background jobs, subshells, signals & trap, cleanup patterns, coproc
10_Error_Handling.md	⭐⭐⭐	set -euo pipefail deep dive, trap ERR, error frameworks, ShellCheck, logging
11_Argument_Parsing.md	⭐⭐⭐	getopts, getopt, self-documenting help, color output, progress bars

Advanced (Professional Techniques)¶

File	Difficulty	Key Topics
12_Portability_and_Best_Practices.md	⭐⭐⭐⭐	POSIX vs bash vs zsh, bashisms, Google Shell Style Guide, security, performance
13_Testing.md	⭐⭐⭐⭐	Bats framework, unit testing patterns, mocking, TDD, CI integration

Projects (Real-World Applications)¶

File	Difficulty	Key Topics
14_Project_Task_Runner.md	⭐⭐⭐	Makefile-like task runner, dependency management, parallel execution
15_Project_Deployment.md	⭐⭐⭐⭐	SSH deployment, rolling deploys, Docker entrypoints, rollback
16_Project_Monitor.md	⭐⭐⭐⭐	Real-time dashboard, alerting, log aggregation, cron integration

Recommended Learning Order¶

Foundation (Week 1): 01 → 02 → 03 → 04
Quickly review shell basics, then dive into parameter expansion and arrays
Intermediate (Week 2-3): 05 → 06 → 07 → 08 → 09 → 10 → 11
Core scripting techniques: I/O, regex, processes, error handling
Advanced (Week 4): 12 → 13
Portability, best practices, and testing
Projects (Week 5): 14 → 15 → 16
Apply everything in real-world projects

Practice Environment¶

# Check your bash version (4.0+ recommended for associative arrays)
bash --version

# Install ShellCheck for static analysis
# macOS
brew install shellcheck

# Ubuntu/Debian
sudo apt install shellcheck

# Install Bats for testing (Lesson 13)
brew install bats-core  # macOS
# or from source: https://github.com/bats-core/bats-core

Linux/ - Linux fundamentals, shell basics
Git/ - Version control (scripts often used in Git hooks)
Docker/ - Container entrypoints use shell scripts
MLOps/ - Automation pipelines