Git

Version Control

• Track changes of files(blobs) as snapshots
• Checkpoint / Tracking
• Collaborative Development

Git Graph

• DAG of Commits
• HEAD pointer: currently looking commit or branch
  • usually points branch
  • Detached HEAD: HEAD pointing commit

Commit

• Snapshot of the project
• Metadata: author, hash, message, etc.

Staging

• Intermediary before commit

3 States of (Tracked) Files

• Modified
• Staged
• Committed

Checkout / Switch

• Change HEAD to specified commit/branch
• Checkout: both commit & branch / switch: -d option for commit

Stashing

• Save / Restore modification on / from stack
• git stash / git restore

Reset (Delete) / Revert

• Reset: deletes commit from DAG
• Revert: add commit that applies reverse patch
  • git revert <commit-id>

Branch

• Pointer to commit
• When creating new commit: HEAD and branch pointed by HEAD points new commit

Creating Branch

• git switch -c <branch> / git checkout -b <branch>: create branch + checkout
• git branch <branch>: no checkout

Merge

• Integrate two branches by creating merge commit
• By default, Fast-Forward (—-no-ff for always create merge commit)

Rebase

• Extract patch from current branch
• Delete commits
• Re-apply patches to base branch
• Simple linear history
• Delete original commit ⇒ metadata changes

Remote

• Remote repository in git host
• Local could also be host

Remote Commands

• Clone: Copy from remote to local
• Push: Reflect changes on the branch to remote
• Fetch: Download changes from remote
• Pull: Fetch then merge
• Blame: Show last modified commit and author for each line

Collaboration w/ Git

• Concise Commits & Branch handles single feature
• Good commit messages
• Good issues
• Git Branching Strategies

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