Commit only part of a file in Git

Question

When I make changes to a file in Git, how can I commit only some of the changes?

For example, how could I commit only 15 lines out of 30 lines that have been changed

Answer 1

I would strongly recommend using SourceTree from Atlassian. (It's free.) It makes this trivial. You can stage individual hunks of code or individual lines of code quickly and easily.