Bash Scripting Mastery

A structured, hands-on repository covering foundational to advanced Bash Shell Scripting, Linux automation, and command-line programming.

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📂 Repository Structure

The scripts are organized into modular, progressive learning modules:

Bash_Scripting/
├── 01_Basics/                  # Variables, user input, arguments, comments
├── 02_Conditionals_and_Logic/  # if-else, case statements, file tests, comparison operators
├── 03_Arithmetic_and_Arrays/   # Integer math, floating point (bc), indexed arrays
├── 04_Loops/                   # while, until, for, select loops, file reading, break/continue
├── 05_Functions/               # Function definitions, parameter passing, local variables
├── 06_Advanced_and_Debugging/  # Signals & traps, readonly variables, debugging techniques
├── Exercise/                   # Hands-on problem sets & mini-projects (Sysinfo, Digital Clock, etc.)
└── practice/                   # Practice task solutions & test outputs

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📚 Module Overview

01_Basics

• 1_hello.sh – Shebang (#!/bin/bash) and basic script output (echo)
• 2_comments.sh – Single-line (#) and multi-line comments
• 3_variables.sh – Variable assignment, naming rules, and expansion
• 4_user_input.sh – Reading interactive terminal input (read)
• 4_user_input_sameline.sh – Prompting input on the same line (read -p)
• 4_read_without_var.sh – Utilizing the default $REPLY variable
• 4_multipleinput_stored_array.sh – Reading space-separated values into an array (read -a)
• 5_pass_arguments.sh – Positional parameters ($1, $2), argument count ($#), and all arguments ($@, $*)

02_Conditionals_and_Logic

• 6_if_statement.sh – Basic conditional tests
• 6_if_else_statement.sh – Two-way conditional branching
• 6_if_elif_statement.sh – Multi-branch decision ladders
• 7_integer_comparsion.sh – Integer comparison operators (-eq, -ne, -gt, -lt, -ge, -le)
• 7_string_comparsion.sh – String equality, inequality, and empty checks (-z, -n, =, !=)
• 8_file_test.sh – File attribute checks (-e, -f, -d, -r, -w, -x)
• 8_append_text_toEOF.sh – Appending output and Here-Documents (cat << EOF)
• 9_logical_and.sh – Logical AND evaluation (&&, -a)
• 9_logical_or.sh – Logical OR evaluation (||, -o)
• 11_case_statement.sh – Multi-branch pattern matching using case
• 11_case_example.sh – Practical menu-driven selection using case

03_Arithmetic_and_Arrays

• 10_arithmetic_operations.sh – Integer arithmetic evaluation ($(( ... )), expr)
• 10_arithmetic_op_float.sh – Floating-point calculations via bc (basic calculator)
• 12_array.sh – Array indexing, length (${#arr[@]}), slicing, and iteration

04_Loops

• 13_while_loop.sh – Standard condition-driven while iteration
• 13_sleep.sh – Execution delays with sleep inside loops
• 13_open_terminal.sh – Process launching and multi-terminal spawns
• 13_read_file.sh – Reading files line-by-line using a while loop
• 13_readfile_IFS.sh – Preserving whitespace with custom Internal Field Separator (IFS)
• 13_factorial.sh & 14_factorial.sh – Iterative factorial calculations
• 14_until_loop.sh – Running loops until a condition evaluates to true
• 15_for_loops.sh – Range ({1..10}) and list-based for iteration
• 15_forloop_cmds.sh – Iterating over command output
• 16_select_loop.sh – Generating interactive numbered menus with select
• 17_break.sh & 17_continue.sh – Loop interruption and cycle skipping

05_Functions

• 18_functions.sh – Function syntax and call semantics
• 18_passing_argument_fun.sh – Function arguments and return status
• 19_local_variable.sh – Scope isolation with local variables
• 19_Example.sh – Modular function architecture

06_Advanced_and_Debugging

• 20_read_only_cmd.sh – Locking variable and function mutability (readonly)
• 21_signals_traps.sh – Intercepting OS signals (SIGINT, SIGTERM) with trap
• 22_debug_script.sh – Shell debugging modes (set -x, set -e, bash -x)

Exercise & practice

• Contains 19 challenge scripts: System Information tool (19_sysinfo.sh), Digital Clock (17_Digital_Clock.sh), Command-line flag parsing (14_getopts_statement.sh), Number reversal, and text search tools.
• 10 multi-step practice tasks for shell automation workflows.

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🚀 How to Run

1. Make any script executable:

   chmod +x 01_Basics/1_hello.sh

2. Run directly:

   ./01_Basics/1_hello.sh

   or with bash:

   bash 01_Basics/1_hello.sh