Visualizing Git: Merge, Rebase, Reset, Revert, Fetch, Pull & Reflog Explained

Introduction

Git is a powerful version‑control tool, but many developers struggle to visualize what happens when they run commands such as git merge, git rebase, git reset, git revert, git fetch, git pull or git reflog. This article, originally created by 21‑year‑old software consultant Lydia Hallie, presents animated GIFs that show the internal mechanics of these commands, making the concepts memorable.

Merge

When you want to integrate changes from one branch into another, you use git merge. Git supports two merge strategies:

Fast‑forward (‑‑ff) : If the current branch has no extra commits beyond the target branch, Git simply moves the branch pointer forward, creating no new commit.

No‑fast‑forward (‑‑no‑ff) : If the current branch has diverging commits, Git creates a new merge commit whose parents are the two branches being merged.

Animated diagrams demonstrate both cases, showing how the commit graph changes after each merge.

Merge Conflicts

If the same line of a file is edited differently on the two branches, Git cannot decide automatically and marks a conflict. The article shows a conflict on README.md where one branch wants “Hello!” and the other wants “Hey!”. It explains how to resolve the conflict manually, stage the resolved file, and commit.

Rebase

git rebase

rewrites history by moving the current branch’s commits onto another base branch, producing new commit hashes. This results in a linear history without merge commits, which can avoid future conflicts. The article also covers interactive rebase , allowing developers to reword, edit, squash, fixup, exec, or drop individual commits before applying them.

Reset

When a commit should be discarded, git reset is used. Two modes are highlighted:

Soft reset : Moves HEAD to a previous commit but leaves the working directory and index unchanged, preserving the changes for a new commit.

Hard reset : Moves HEAD and resets both the index and working directory to the specified commit, discarding all subsequent changes.

Examples show resetting away unwanted commits while optionally keeping file modifications.

Revert

git revert

creates a new commit that undoes the changes introduced by a specific earlier commit, without rewriting history. The article demonstrates reverting a commit that added index.js, preserving the linear commit graph.

Cherry‑pick

git cherry-pick

copies a single commit from another branch onto the current branch, useful when only a specific change is needed. An example moves a commit that modifies index.js from dev to master without merging the whole branch.

Fetching and Pulling

git fetch

downloads new objects and refs from a remote repository without altering local branches. git pull combines fetch followed by a merge, automatically integrating the fetched changes into the current branch. Animated diagrams illustrate the data flow and resulting branch updates.

Reflog

git reflog

records every move of HEAD, providing a safety net for recovering from mistakes. The article shows how to view the reflog, identify a previous state (e.g., HEAD@{1}), and use git reset to restore that state.

Overall, the visual approach helps developers grasp the effects of each command on branch topology, commit history, and working files, reducing confusion and preventing common errors.