Bash Scripting Basics made Easy

This document provides a list of basic Bash scripting commands and concepts to help you get started with writing and executing scripts in a Linux environment.

Script Structure

• #!/bin/bash: Shebang to specify the script interpreter.
• #: Comment line.

Variables

• variable_name=value: Define a variable.
• $variable_name: Access the value of a variable.

Input and Output

• echo [text]: Print text to the terminal.
• read [variable]: Read input from the user.

Conditional Statements

• if [ condition ]; then ... fi: Basic if statement.
• if [ condition ]; then ... else ... fi: If-else statement.
• if [ condition ]; then ... elif [ condition ]; then ... else ... fi: If-elif-else statement.

Loops

• for variable in list; do ... done: For loop.
• while [ condition ]; do ... done: While loop.
• until [ condition ]; do ... done: Until loop.

Functions

• function_name() { ... }: Define a function.
• function_name: Call a function.

File Operations

• touch [file]: Create an empty file.
• cat [file]: Display file content.
• > [file]: Redirect output to a file (overwrite).
• >> [file]: Redirect output to a file (append).

String Operations

• ${#string}: Get the length of a string.
• ${string:position:length}: Extract substring.

Arrays

• array_name=(value1 value2 value3): Define an array.
• ${array_name[index]}: Access array element.
• ${#array_name[@]}: Get the length of an array.

Exit Status

• exit [status]: Exit the script with a status code.
• $?: Get the exit status of the last command.

Error Handling

• command || { echo "Command failed"; exit 1; }: Execute a command and handle errors.

Debugging

• bash -x script.sh: Run a script in debug mode.

These commands and concepts should help you get started with basic Bash scripting.