Opening a Terminal
A terminal is the window where you type commands; the shell (Bash) is the program inside it that runs them.
Linux
Open the Terminal application (often Ctrl + Alt + T). Bash is usually the default shell.
macOS
Open Terminal (in Applications → Utilities). The default shell is
zsh, which runs almost everything in this course. To use Bash itself,
type bash. macOS includes an old Bash 3.2; install a current version
with Homebrew: brew install bash.
Windows
- WSL (Windows Subsystem for Linux) — the best option. Run
wsl --installin PowerShell (as administrator), restart, and you get a real Linux environment with Bash. - Git Bash — installed with Git for Windows; good for everyday commands and Git, though a few Linux tools behave slightly differently.
Check your shell and version
# illustrative
echo "$SHELL"
bash --version | head -n 1
/bin/bash
GNU bash, version 5.3.3(1)-release (x86_64-pc-linux-gnu)
Your path and version will differ. Most examples in this course work on Bash 4 and later; newer features are pointed out when they appear.
The prompt
The terminal shows a prompt when it's ready for a command — often something like:
ada@laptop:~$
That's your username, the computer's name, the current folder (~ means
your home folder), and $. In this course, commands are shown without the
prompt so you can copy them; lines starting with $ in a terminal
transcript show what was typed.