Shell
The program inside the terminal that reads your commands and runs them — bash and zsh are the common ones.
Not the same as the terminal
The terminal is the window. The shell is the program running inside it that reads what you type — which is why the same commands behave the same in any terminal app, and why the quirks belong to bash or zsh rather than to the window.
Where it bites
The shell expands things before the command ever sees them. `*.js` is turned into a list of matching files first, which is why quoting matters: `find . -name “*.js”` and `find . -name *.js` are different requests.
Covered in these lessons
Related terms
Where this comes up
Also written as shell, bash, zsh. Checked 2026-08-06.