Explore how to declare and use variables in bash scripts, including environment variables, user defined variables, readonly mode, and accessing values with dollar signs, plus reading input and creating files.

Explore how to use comparison operators in shell scripting to test variables, strings, and conditions, and learn how equal, not equal, greater than, and less than guide decision making.

Explore conditional statements using if and else, not equal to operator, and case structures to execute code blocks based on conditions, with nested conditions and user input.

Explore bash loop statements: while, for, and until; control flow with break and continue, iterate with arrays and echo, and build infinite or user-driven loops.

Learn how positional arguments pass values to a shell script, access them with $1 and $2, and understand shell parameters, variables, and predefined special parameters.

Explore exit codes of shell commands, where 0 means success and non-zero signals failure, and learn to view, set, and use them in scripts with $?.

Explore here documents in shell scripting by passing multi-line strings to commands with a delimiter token and ending input on its own line using cat, wc, or sort.

Learn how to create and use functions in shell scripts, return values, pass different arguments, and build abstractions like a backup function that copies a directory to a destination.

Learn to pass and parse Linux shell script arguments with positional and named options, using getopts and shift to iterate and validate parameters.