Bash Tutorial · Bash Basics · Lesson 1 of 30
Bash Introduction
What Bash is, where you'll use it, and how the examples in this tutorial work.
What is Bash?
Bash (the Bourne Again SHell) is the command-line shell of most Linux systems and the language of countless scripts that build, test, deploy and operate software. A shell reads commands, runs programs, and connects them together; a shell script is a file of those commands that runs on its own.
You'll meet Bash everywhere:
- Servers and containers: almost every Linux server and Docker image has a shell.
- CI/CD pipelines: GitHub Actions, GitLab CI and Jenkins steps are mostly shell commands.
- Developer tooling: setup scripts, Git hooks, Makefiles and one-off data clean-ups.
- macOS and Windows: macOS uses zsh by default (very similar), and Windows has Bash through WSL.
How this tutorial works
Every example is a real Bash script that was run on Linux; the output shown is exactly what it printed. Each one
starts in an empty directory, so examples create the files they need. Try them in a terminal: copy the code into
a file such as demo.sh and run bash demo.sh.
echo "Hello from Bash!"
echo "Today we have $(ls / | wc -l) top-level directories on this machine"
name="developer"
echo "Welcome, $name"
Output
Hello from Bash! Today we have 26 top-level directories on this machine Welcome, developer
Run this on your computer — see “Get Started” for setup.
Test yourself
What is a shell script?
A compiled binaryA file of shell commands that runs as a programA configuration file for SSHA Python module
Show answer
Answer: A file of shell commands that runs as a program
Scripts automate what you'd otherwise type by hand.