class: center, middle # Git II .copyright[ <a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/4.0/88x31.png" /></a> ** [Pat Pannuto](http://patpannuto.com) / Marcus Darden ** ] --- # Goin' Old School Lecture this week will use the whiteboard during class. These slides capture the lecture notes / plan. We will also post some supplemental material on the [course homepage](https://c4cs.github.io/#schedule) --- # Repo Sandbox: In the Beginning... ``` 1 <- 2 <- 3 master ``` ## Activity 1. Create empty repo, add commits 1, 2, 3 and record hashes 2. Check out .git/HEAD - What is "HEAD"? --- # Repo Sandbox: A New Branch ``` 1 <- 2 <- 3 master \ <- 3 <- 4 no_two ``` ## Activity 1. `git checkout <commit 1 hash>` - What is 'detached HEAD' state? 2. `git branch no_two` 3. `git checkout no_two`, add commits 3 & 4 and record hashes - HEAD is reattached 4. Explore .git/refs/heads/... - What is a branch? --- # Repo Sandbox: The First Merge ``` 1 <- 2 <- 3 <- M1 master \ / <- 3 <- 4 <- no_two ``` ## Activity 1. A new alias! 2. `git checkout master` - look around 3. `git merge no_two` - 'merge' means 'merge into' - look around --- # Repo Sandbox: Fast Forward ``` <- 5 master, fast_five / 1 <- 2 <- 3 <- M1 \ / <- 3 <- 4 <- no_two ``` ## Activity 1. `git checkout -b fast_five`, add commit 5, record hash - look around 2. `git checkout master` 3. `git merge fast_five` - What does 'fast forward' mean? - look around --- # Repo Sandbox: More Branches ``` <- 6 add_six / 1 <- 2 <- 3 <- M1 <- 5 master, fast_five \ / \ <- 3 <- 4 <- no_two <- 7 add_seven ``` ## Activity 1. `git checkout -b add_six` - look around 2. `git branch add_seven master` - look around 3. Add commit 6, record hash - look around 4. `git checkout add_seven`, add commit 7, record hash - look around --- # Repo Sandbox: Merge en Trois ``` <- 6 <- add_six / \ 1 <- 2 <- 3 <- M1 <-- 5 <- M2 master \ / \ / <- 3 <- 4 <- no_two <- 7 <- add_seven ``` ## Activity 1. `git branch -d fast_five` 2. `git checkout master` 3. `git merge add_six add_seven` - Can merge *n* branches at once (octopus!) - Creates a 'merge commit', why? --- ## Remotes 1. Show how the graph varies based on machine - Sync'ing is all about syncing graph objects 2. Open GitLab, explain what it is 3. Push demo to GitLab 4. Pull down a clone 5. Make changes 6. Push up 7. Fetch, then merge 8. Repeat with pull 9. Pushing, pulling, and _tracking_ branches --- ## Rewriting History: Squashing, Rebasing 0. Commit everything. Branch often. 1. Create a feature branch, several commits, squash