Git & Version Control

A snapshot of staged changes saved to the repository history, identified by a unique SHA hash.

"Each commit should represent a single logical change — atomic commits make it easier to revert specific bugs."

A lightweight movable pointer to a commit that lets you work on features or fixes in isolation from the main codebase.

"I created a feature branch for the OAuth integration so my changes don't affect the main branch during development."

Incorporating changes from one branch into another, creating a merge commit that preserves both histories.

"After code review approval we merge the feature branch into main — the merge commit records when and what was integrated."

Moving or replaying commits from one branch onto another base, resulting in a linear history without merge commits.

"Before opening the PR I rebase onto main so my branch has the latest changes and the history is clean and linear."

Applying a specific commit from one branch to another without merging the entire branch history.

"The hotfix was cherry-picked from main into the release branch so we could ship the critical bug fix without taking other changes."

Temporarily shelving uncommitted changes so you can switch context, then reapply them later.

"I stashed my in-progress work before pulling the urgent hotfix branch, then popped the stash to resume."

A binary search through commit history to find the commit that introduced a bug, using git bisect good/bad.

"I used git bisect to narrow 200 commits down to the exact one that broke the auth flow — found it in 8 steps."

A reference pointing to the currently checked-out commit — usually the tip of the active branch.

"HEAD points to the latest commit on my branch — git log HEAD~3 shows the last three commits."

State where HEAD points to a commit directly rather than a branch, meaning new commits won't be tracked by any branch.

"I ended up in detached HEAD state after checking out a tag — I created a new branch to save my experimental commits."

A merge that simply moves the branch pointer forward because the target has no diverging commits — no merge commit is created.

"The merge was a fast-forward — main hadn't changed since I branched, so Git just moved the pointer forward."

Combining multiple commits into a single commit before merging, for a cleaner project history.

"We squash all commits on a feature branch into one before merging — the PR's 23 WIP commits become a single meaningful commit."

Creating a new commit that undoes the changes introduced by a previous commit, preserving history.

"Rather than resetting, we reverted the bad deploy commit — the revert is visible in the log and safely undoes the change."

Moving the branch pointer to a previous commit. --soft keeps changes staged, --mixed unstages them, --hard discards them.

"I used git reset --soft HEAD~2 to undo my last two commits while keeping the changes staged for a cleaner re-commit."

A named reference to a specific commit, typically used to mark release versions (v1.0.0, v2.3.1).

"We create a tag for every production release — git tag v1.4.2 so we can check out any historical release instantly."

A copy of a repository under your own account, used to contribute to projects you don't have write access to.

"I forked the open-source library, made my bug fix in the fork, then opened a pull request to the upstream repository."