Have you ever copied index_backup.html before making a big change? Git does that copying for you — automatically, cleanly, as many times as you like. This lesson covers what Git actually records, and clears up the confusion between Git and GitHub.
Where backup-by-filename breaks down
Manual backups turn into this very quickly:
index.html
index_backup.html
index_backup2.html
index_final.html
index_final_really-final.htmlA few days later, nobody knows which one is current or what changed between them. And even a one-character edit means another full copy of the file.
Git solves this differently: it records the history of changes without multiplying your files.
Git records “the state at that moment” under a name
Recording in Git is called a commit. When you commit, the contents of your folder at that moment are recorded, along with a short message about what you did.
commit 3 ← now "Add the thank-you message to the form"
commit 2 "Add the favorites list"
commit 1 "Build the page skeleton"What this buys you:
- You can go back — “I changed it and it broke” is solved by rewinding one commit
- You can remember what you did — the messages stay in the history, which future you will thank you for
- You can make big changes calmly — with a record behind you, ambitious rewrites stop being scary
Git and GitHub are two different things
This is the first thing that trips people up. Similar names, different jobs.
| Git | GitHub | |
|---|---|---|
| What it is | A tool that records changes (software) | A place that stores those records (web service) |
| Where it runs | On your own computer | On the internet |
| What you lose without it | Your history | Everything, if your computer dies |
| Cost | Free | Free for personal use |
Git alone keeps your history. Putting it on GitHub gives you a backup, a way to share, and the ability to publish the site directly.
Only three words to learn at first
Git has a lot of vocabulary, but you only need these to begin.
| Word | Meaning |
|---|---|
| Repository | The folder whose history is being recorded — the unit you decided to manage with Git |
| Commit | Recording the current state, or one such record |
| Push | Sending your local records to GitHub |
With these three, the commands in the coming lessons will make sense.
Summary of this lesson
- Git is a tool that records changes so you can return to any earlier state. It runs on your machine
- The unit of recording is a commit — the whole state at that moment, with a message attached
- GitHub is the web service that stores those records, giving you backup, sharing, and publishing