Git - Intro and Theory

Slides for introduction to Git. Explaining: how a personal repo is designed, how branches are designed, and how the Git mindset is different from the SVN mindset.

Transcript

1. ©2011 Sundog | www.sundoginteractive.com Sundog Git Tech Talk November 25, 2011
2. ©2011 Sundog | www.sundoginteractive.com Introduction
3. ©2011 Sundog | www.sundoginteractive.com History • Roots in Linux – Written by Linus Torvalds • Motivation – BitKeeper changed license • Create new VCS, learned from BitKeeper • Keep distributed flow • Strong safeguards against corruption • High-performance • Written April 3-7, 2005
4. ©2011 Sundog | www.sundoginteractive.com Technology • Rough Overview: • Self-sufficient repository • Lightweight branches • Undo-able • Very popular
5. ©2011 Sundog | www.sundoginteractive.com Technology • Basic terms • Git directory • Working directory
6. ©2011 Sundog | www.sundoginteractive.com Technology • Working Directory • Develop here • Git watches
7. ©2011 Sundog | www.sundoginteractive.com Technology • Git Directory • The repository • Important ones • Objects = history. • Refs = pointers • Index = tracked files • HEAD = current branch
8. ©2011 Sundog | www.sundoginteractive.com Technology • Commit Theory • Basically Directed node graph.
9. ©2011 Sundog | www.sundoginteractive.com Technology • Commit Theory • Basically Directed node graph.
10. ©2011 Sundog | www.sundoginteractive.com Technology • Commit Theory • Basically Directed node graph.
11. ©2011 Sundog | www.sundoginteractive.com Technology • Chained Commits • Commit has 0, 1, or 2 parents • Each commit is a directory snapshot
12. ©2011 Sundog | www.sundoginteractive.com Technology • Branches • A branch = pointer to a commit
13. ©2011 Sundog | www.sundoginteractive.com Technology • Changing Branches • HEAD = pointer to branch pointer • To change branches, just move HEAD pointer
14. ©2011 Sundog | www.sundoginteractive.com Technology • Branches Diverge • Checkout testing, commit, checkout master, commit. • It’s all the same!
15. ©2011 Sundog | www.sundoginteractive.com Technology • Merging • Three-way merge • Chooses base for you
16. ©2011 Sundog | www.sundoginteractive.com Technology • Merging • Calculates, applies patches • ‘Merge Commit’ is commit with two parents
17. ©2011 Sundog | www.sundoginteractive.com Technology • Merge Conflict • Pauses merge, asks user to manually merge • Re-stage to mark as resolved
18. ©2011 Sundog | www.sundoginteractive.com Technology • Remotes • Remote repository • Remote branch is indicator only • Used for basing work on
19. ©2011 Sundog | www.sundoginteractive.com Technology • Syncing w/ Remote • Remote is updated • We also have commits
20. ©2011 Sundog | www.sundoginteractive.com Technology • Update from Remote • ‘Fetch’ copies remote commits to local repo
21. ©2011 Sundog | www.sundoginteractive.com Technology • Multiple Remotes • Multiple pointers • Fetch commits chain • use to merge changes • base for new branches
22. ©2011 Sundog | www.sundoginteractive.com Practical Use • Four stages for files
23. ©2011 Sundog | www.sundoginteractive.com Practical Use • Basic commit process • git init (create README file) • git add README • git commit –m ‘Commit message.’
24. ©2011 Sundog | www.sundoginteractive.com Practical Use • Basic branch process • git branch featureA • git checkout featureA (make changes/additions) • git add (files) • git commit –m ‘Add feature A’
25. ©2011 Sundog | www.sundoginteractive.com Practical Use • Basic merge process • git checkout master (make changes/additions) • git commit –a –m ‘Add feature A’ • git merge featureA • git branch –d featureA
26. ©2011 Sundog | www.sundoginteractive.com CLI Example 1 • Try committing • Create repo • Commit directory to repo • Create a file, modify a file, commit them
27. ©2011 Sundog | www.sundoginteractive.com CLI Example 2 • Try Branching • Work on experimental feature. Use a branch • Merge experimental feature back to master
28. ©2011 Sundog | www.sundoginteractive.com CLI Example 3 • Try cloning • Add remote repository • Clone it into local repo • Branch, develop, and push to remote
29. ©2011 Sundog | www.sundoginteractive.com GitHub Example 1 • Try cloning • Add remote repository • Clone it into local repo • Branch, develop, and push to remote
30. ©2011 Sundog | www.sundoginteractive.com Practical Use • Common Commands • git status • git add [file] • git commit • git diff (--staged) • Destructive Commands • git reset [file] • git rm [file]
31. ©2011 Sundog | www.sundoginteractive.com