About this repository

This is a learning repository. The repository structure described in this file is in this repository. The commit IDs have changed, but the basic structure of commits is here. You can follow along with the commands to learn this command---in fact, it's encouraged.

This repository is part of Travis Swicegood's talk titled, Git's Meat Cleavers. If you'd like to learn more about Git, you can see Travis talk around the country on the topic, or pick up either of his books:

• Pragmatic Version Control using Git - An introduction to version control and the concepts of Git.
• Pragmatic Guide to Git - A quick-start guide for those familiar with version control for those looking to transition to Git from another tool.

Rebasing

Rebasing takes one series of commits--normally a branch--and replays them on top of another commit, also normally a branch.

Consider a repository that looks like this when you run git log --oneline --graph --all:

prompt> git log --oneline --graph --all
* ce38ccb f
| * 5a2eaf3 e
| * 5a00102 d
|/
* 2b449a0 c
* 1674c67 b
* 0f5f8d0 a
* c1d1e5d README driven development

Commits e and f are on a branch called other. It's created from commit c on the master branch, which later had a commit f added to it.

Rebasing other on top of master, takes the two commits from other and replays them after the last commit inside the master branch. It looks something like this:

prompt> git checkout other
Switched to branch 'other'
prompt> git rebase master
* 19b43c5 e
* 519c589 d
* ce38ccb f
* 2b449a0 c
* 1674c67 b
* 0f5f8d0 a
* c1d1e5d README driven development

Now, e and f come after the latest commit in master.

Warning

Be careful with rebase. Git uses the parent of a commit as part of it's commit ID calculation. Rebasing changes that ID, which leads to trouble when you share code with other developer's that has been rebased.

The rule of thumb is to rebase code to your heart's content, until you've shared your code. Once you've pushed your code to another server, don't rebase that part of your repositories.

Put another way, never rebase a branch that you've shared, but go to town rebasing your local branches on top of that shared code.