1. Patrick Cozzi University of Pennsylvania CIS 565 - Fall 2012
Source Control Primer
Also called revision control or version control.
Patrick Cozzi
University of Pennsylvania
CIS Fall 2012

2. Why Source Control? How do two people collaborate on the same code??
Dropbox?
How do two hundred people collaborate?

3. Why Source Control? How do we backup our code?
How do we change the same file?
How do we get a history of changes?

4. Why Source Control?
How do we make big or risky code changes without affecting the stable version?
How do we work on new versions and still support old versions?
Feature branches.
Release branches.

5. Popular Tools
P4 and SVN (subversion) are centralized. Git is distributed.
Git is separate from github, but github is popular for hosting.
Images from and

6. Centralized Server holds a centralized repository
Clients have a revision
This follows P4.
The server has the entire repository (depot in P4) including history. Clients have a local snapshot.

7. Centralized
This follows P4

8. Centralized
This follows P4
Submit

9. Centralized
This follows P4

10. Centralized
Get Latest Revision

11. Centralized Modify/add/remove files
Files can be read-only (P4) or not (SVN)
Modify/add/remove files

12. Centralized
Files can be read-only (P4) or not (SVN)
Submit

13. Centralized
Get Latest Revision

14. Distributed All machines have a full copy of the repository
Repositories can be cloned
Repositories can be pushed to and pulled from other machines

15. Distributed git init // Add files to directory git add *
git commit –a –m ‘<description>’
Create a local repo
Locally commit changes

16. Distributed Clone a remote repo
git clone
Clone a remote repo

17. Distributed git commit –a –m ‘<description>’
Locally commit changes

18. Distributed
git push
Push changes to other repos

19. Distributed
git pull
Pull changes from other repos

20. Summary We are using git this semester - distributed source control
Use source control for everything, not just code
The initial pain will pay dividends for the rest of the semester and your career.
Learn the command line, then use GUIs if desired.

21. Git Resources Create initial account - https://github.com/signup
Get an edu account -
Setup git -
Guide -
Cheat sheet -
Join CIS