Git allows developers to integrate changes across branches through merging or rebasing. Merging joins development histories together but can lead to merge conflicts and "merge madness". Rebasing forwards local commits to the updated upstream head, avoiding unnecessary merge commits and keeping a linear history. Developers can use Git's interactive rebase mode to reorder, edit, drop, squash, or split commits when changing a branch's history before integrating it into another branch.

1. Change History With Git
using rebase to maintain sanity

2. Integrating changes across
branches

3. merge
Join two or more
development histories
together

4. merge
Join two or more
development histories
together

5. merge madness

6. rebase
Forward-port local commits
to the updated upstream
head

7. rebase
Forward-port local commits
to the updated upstream
head

8. rebase sanity

9. Changing history with
git rebase interactive mode

10. interactive mode
• reorder
• edit
• drop
• squash
• split

11. interactive mode
$ git checkout my_feature_branch
$ git rebase --interactive master

12. changing history
$ git checkout master
$ git rebase --interactive e0a3a3

13. Warning!
• BAD for pushed commits

14. Resources
• screencast: http://peepcode.com/products/git
• gitx: http://gitx.frim.nl