What a repository actually is

A repository — repo for short — is a folder whose every change is recorded. Not just the current state of your files: every version of them, with a note about what changed and when.

Think of a document where every save is kept forever and labelled. You can read any old version, compare two of them, or go back. A repo does that for a whole folder of files.

• A commit is one recorded change, with a short message you write.
• The history is all the commits, in order.
• The repo is the folder plus that history.