Bash Scripting

The command line becomes powerful when you stop typing the same sequences and start writing scripts that run them for you. This series takes you from your first executable file to scripts with variables, arguments, logic, loops, and reusable functions — the complete foundation for Bash automation.

Before you start

You should be comfortable with Pipes and Redirection before working through this series — scripts use pipeline concepts constantly.

• Your First Bash Script

  ---

  The shebang line, chmod +x, and where to store scripts so they're available system-wide or team-wide.

• Variables and Quoting

  ---

  Why quoting bugs are the #1 source of Bash failures — and the rules that prevent them.

• Arguments and Exit Codes

  ---

  $1, $@, $#, and $? — how to accept input and communicate success or failure to callers and pipelines.

• Conditionals

  ---

  if/elif/else and the [[ ]] operator — file tests, string comparisons, and numeric checks that make decisions reliably.

• Loops

  ---

  for and while — how to iterate over files, arrays, and command output without the bugs that come from getting it wrong.

• Functions

  ---

  Define, scope, and reuse logic — the local variable rule, returning values, and the main "$@" pattern that keeps large scripts readable.