Tools·basic
Terminal
Where you type commands instead of clicking. Your computer's text interface.
The terminal is a text window where you type commands and the computer types back. The Terminal app on Mac. Command Prompt or PowerShell on Windows. These are terminals.
Instead of double-clicking a folder, you type cd Desktop/Mosaic. Instead of dragging a file to the trash, you type rm file.txt. Slower at first. After a week it's faster than the mouse for a lot of things.
Mosaic introduces the terminal gently in Chapter 0-3. By the end of Arc II you're comfortable in it. It's where you run Python, manage Git, and start Claude Code.