Shell Scripting Roadmap for Beginners to Advanced

Shell scripting is essential for automating tasks in Unix/Linux environments. Here’s a structured roadmap to mastering it.

Table of Contents

1. Basics of Shell & Linux Commands

Before diving into scripting, familiarize yourself with Linux basics.

Learn the Command Line

Understanding the Shell (Bash, Zsh, etc.)
File system navigation (cd, ls, pwd, find)
File operations (cp, mv, rm, touch, mkdir, rmdir)
Viewing and editing files (cat, less, more, nano, vim, grep, awk, sed)
Permissions and ownership (chmod, chown, chgrp)
Process management (ps, kill, jobs, bg, fg, top, htop)
Networking commands (ping, curl, wget, netstat, ss, ifconfig, nslookup)
Package management (apt, yum, dnf, brew, snap)

2. Introduction to Shell Scripting

Shell Script Basics

What is a shell script?
Writing and executing a script (.sh files)
Using chmod +x to make scripts executable
Adding the shebang (#!/bin/bash)

Variables and Data Types

Declaring variables
Environment vs. local variables
Special variables ($0, $1, $2, $#, $@, $?, $$, $!)
Read user input (read command)

3. Control Structures

Conditional Statements

if, else, elif
Using test conditions ([ condition ] or [[ condition ]])
case statement (switch-case alternative)

Looping Constructs

for loops
while loops
until loops
break and continue statements

4. Functions & Scripting Best Practices

Defining functions
Calling functions within scripts
Using function return values
Modular scripting (reusable functions)
Debugging (set -x, set -e, trap)

5. Advanced Shell Scripting

Text Processing

awk (pattern scanning and processing)
sed (stream editor for modifying text)
grep (pattern matching)
Regular expressions in shell scripts

File Handling

Reading and writing files (cat, echo, tee)
Redirection (>, >>, <)
Piping (|)

Process Automation & Job Scheduling

cron jobs (crontab -e)
at command (schedule one-time tasks)
Running background jobs (nohup, &, disown)

6. System Administration with Shell Scripting

User management (adduser, deluser, passwd)
Disk usage monitoring (df, du)
System logs (/var/log)
Network configuration and automation

7. Scripting for DevOps & Cloud

Writing scripts for Docker container management
Automating AWS/GCP tasks using CLI tools
CI/CD pipeline automation with shell scripts

8. Learning Resources

Books: “Linux Command Line and Shell Scripting Bible”
Online Courses: Udemy, Coursera, Linux Academy
Practice: Write scripts to automate daily tasks