Bash Primer

A comprehensive reference for Bash shell scripting — from basics to advanced topics.

Introduction

#	Topic	Description
01	Unix Shells	Shell overview, history, and major shell families
02	Shell Configuration Files	Login vs non-login shells, .bashrc, .profile, etc.

Shell Basics

#	Topic	Description
03	Bash Keywords	Reserved words and built-in keywords
04	Interactive vs Non-Interactive Shells	Shell modes and how to detect them
05	Auto-Completion	Tab completion and programmable completion
06	History Management	Command history, search, and HISTCONTROL
07	Shell Prompt	Customizing PS1, escape sequences, colors
08	Shell Scripts	Writing and executing shell scripts, shebang

Variables

#	Topic	Description
09	Shell Variables	Variables, naming, types, and arithmetic
10	Environment Variables	export, child processes, and persistence
11	PATH	The PATH variable and command lookup
12	sudo and Variables	How sudo affects the environment
13	Built-in Shell Variables	HOME, PWD, SHELL, USER, etc.
14	Special Variables	$?, $$, $!, $@, $#, and more

Input / Output & File Operations

#	Topic	Description
15	Input and Output	echo, printf, and read
16	File and Directory Operations	cp, mv, rm, mkdir, find, tar, etc.
17	Shell Expansions	Brace, tilde, parameter, arithmetic expansions
18	Globbing (File Expansion)	Wildcards: *, ?, […], extended globs

Tests & Operators

#	Topic	Description
19	test Command	test, [, and [[ syntax
20	Test Operators	File, string, and integer test operators
21	Bash Operators	Assignment, arithmetic, logical, test, and redirection operators

Control Flow & Data Structures

#	Topic	Description
22	Conditional Statements	if…else, case, and select
23	Loops	for, while, until, break, and continue
24	Arrays	Indexed arrays, associative arrays, and mapfile
25	Functions	Defining functions, local variables, return values
26	Alias	Creating and managing command aliases

Commands & Redirection

#	Topic	Description
27	Exit Status	Return codes, $?, and error handling
28	Command Execution	How Bash finds and runs commands
29	Command Substitution	$(…) and backtick syntax
30	Command Chaining	&&, `
31	Redirection	>, >>, 2>, &>, here-docs, here-strings

Processes & Job Control

#	Topic	Description
32	Background Processes	&, jobs, fg, bg
33	SIGHUP	Handling hangup signals, nohup, disown
34	Daemon Processes	Running long-lived background services
35	Sub-Shells	Parenthesized commands and subshell scope

Advanced Topics

#	Topic	Description
36	Process Substitution	<(…) and >(…) syntax
37	Regex in Bash	=~ operator, grep, sed, awk
38	trap	Signal handling and cleanup routines
39	Shell Options	set, shopt, and common options

Program Arguments & Options

#	Topic	Description
40	Command-line Arguments	Positional parameters and shift
41	Command-line Options	getopts and option parsing
42	Processing Options	Advanced option processing patterns

Debugging

#	Topic	Description
43	Debugging Bash Scripts	set -x, set -e, trap DEBUG, and more

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Project Structure

#primer-bash/
├── docs/          ← Markdown notes (one per topic)
├── pics/          ← Diagrams and images
├── codes/         ← Example scripts and supporting files
└── README.md      ← This file