git-chetsheet-2.md

Git Syntax Cheat Sheet

1. HEAD

• HEAD refers to the latest commit on the current branch.
• HEAD^ refers to the parent commit of HEAD.
• HEAD^^ refers to the grandparent commit, and so on.

2. Tilde ~

• HEAD~n: Refers to the commit n commits before HEAD. For example, HEAD~2 refers to the second ancestor commit.

3. Caret ^

• HEAD^n: Refers to the nth parent of a merge commit, useful for merge commits with more than two parents.

4. Double Dot ..

• A..B: Refers to all commits reachable from B but not from A (commits in B that are not in A).

5. Triple Dot ...

• A...B: Refers to all commits in both A and B, except for those reachable by both (symmetric difference).

6. Plus Sign +

• +branch_name: Forces an update by discarding any in-progress changes.

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Examples

Example 1: Reviewing History

• git log HEAD~3..HEAD: Shows the log for the last three commits up to the current HEAD.

Example 2: Comparing Branches

• git diff master..feature: Shows the difference between the master branch and the feature branch, displaying changes exclusive to feature.

Example 3: Understanding Differences

• git log branchA...branchB: Lists all commits that are in branchA or branchB but not in both, helping to understand divergent histories.

Example 4: Resetting Changes

• git reset --hard HEAD^: Moves the current branch pointer to the parent of the current commit, discarding all changes since that commit.

Example 5: Forced Update

• git push origin +master: Forcefully updates the remote master branch to match the local master, potentially overwriting changes on the remote.