git add
git add <file> | . | -p
Risk: Safe
What it does
Puts changes in the box (staging area).
When to use it
When a change is ready to save.
Example
$ git add index.htmlPut one file in the box.
$ git add .Put all changes here in the box.
$ git add -pPick pieces of a change, one by one.
Learn it in: The Box · Official docs