Linux Shell Scripting Study Notes

Arrays in Bash

Learn how to create, index, and iterate indexed and associative arrays in Bash, and how to use them to write scripts that handle lists of data correctly.

awk Basics

Learn awk, the field-oriented text processing language, to extract columns, compute aggregates, and transform structured text like logs and CSVs.

Background Jobs and nohup

Learn to run and manage background jobs with &, jobs, bg/fg, and disown, and keep long-running processes alive after logout using nohup and disown.

Basic Networking Commands (ping, curl, ss)

Learn the essential command-line tools for diagnosing connectivity, testing HTTP endpoints, and inspecting open sockets and listening ports on Linux.

chmod and chown

Learn how to change file permissions with chmod (symbolic and octal modes) and change ownership with chown and chgrp, including recursive usage and special bit…

Command-Line Arguments and getopts

Learn how Bash scripts receive positional parameters, how to shift and iterate over them, and how to build proper option parsing with getopts.

Common Shell Scripting Pitfalls

A field guide to the mistakes that silently break Bash scripts — unquoted variables, wrong test operators, subshell scoping, and error-handling gaps.

Conditionals in Bash (if, case)

Master Bash's conditional constructs — if/elif/else, test expressions, [[ ]] versus [ ], and case statements — to make scripts branch correctly on real-world c…

Copying, Moving, and Renaming

How cp and mv handle copying, moving, and renaming files and directories, including recursive copies, preserving attributes, and safe overwrite behavior.

Creating and Removing Files and Directories

How to create empty files and directory trees with touch and mkdir, and safely remove them with rm and rmdir, including the dangers of recursive deletion.

Disk Usage and Management (df, du, mount)

Learn how to inspect filesystem capacity, measure directory sizes, and understand how block devices get attached to the Linux directory tree via mounting.

Environment Variables and PATH

Understand how environment variables are set, exported, and inherited by child processes, and how PATH determines which executable a bare command name resolves…

Exit Codes and Error Handling

Understand how every command reports success or failure through its exit status, and how to build scripts that detect and respond to errors reliably.

File Permissions Explained (rwx)

Understand the Linux permission model — read, write, and execute bits for owner, group, and others — and how ls -l output maps to those permissions.

Finding Files with find and locate

Master the two main Linux file-search tools: the real-time, highly flexible find command and the fast, index-based locate command, including when to use each.

Functions in Bash

Learn how to define reusable Bash functions, pass arguments and return values, manage variable scope with local, and organize larger scripts around them.

Getting Help: man, --help, and info

How to find authoritative documentation for any Linux command using man pages, --help output, and the info system, plus tips for searching and navigating them…

grep and Regular Expressions

Master text searching with grep and the regular expression syntax that powers it, from basic literal matches to extended regex patterns and useful flags.

Killing and Signaling Processes

Understand Unix signals and the kill, killall, and pkill commands to gracefully terminate or forcibly stop misbehaving processes.

Linux & Shell Scripting Interview Questions

A curated set of frequently asked Linux and Bash interview questions with model answers, spanning fundamentals, scripting, and troubleshooting scenarios.

Linux & Shell Quick Reference

A condensed cheat sheet consolidating the most frequently used Linux commands, Bash syntax, and shortcuts covered throughout this course for fast lookup.

Loops in Bash (for, while, until)

Learn Bash's three loop constructs — for, while, and until — plus loop control with break and continue, to iterate over lists, files, and command output safely.

Monitoring Processes with ps and top

Learn to inspect running processes with ps snapshots and the interactive top monitor, reading CPU, memory, and state columns to diagnose system load.

Navigating the Filesystem (cd, pwd, ls)

Practical mastery of moving around the Linux directory tree using cd, pwd, and ls, including absolute vs relative paths and useful ls flags for everyday work.