Understanding Git Merge vs Rebase: When and How to Use Each

1. Git Working Principles

Git is a distributed version‑control system loved by developers worldwide for its simple, efficient design that can handle projects of any size. It consists of four core areas: the Working Directory, the Staged/Index area, the Local Repository, and the Remote Repository.

The Working Directory is where you edit files. After running git add, changes move to the Staged area, indicating they are ready to be committed. git commit stores those changes permanently in the Local Repository, which keeps the complete history. The Remote Repository enables multiple developers to pull and push code for collaboration and backup.

2. How Git Merge Works

Assume the master branch has initial commits A1 and A2. A developer creates a feature branch from A2 and adds commits A3 and A4. Meanwhile, another developer adds commit A5 to master. When merging, Git creates a special merge commit M6 that combines changes from A5 (master) and A4 (feature), producing a diamond‑shaped commit graph that preserves the full branch history.

3. How Git Rebase Works

Using the same initial situation, the rebase command moves the feature branch commits onto the latest master commit (A5) without creating a merge commit. The original A3 and A4 become new commits A3* and A4* with different hashes, resulting in a linear history that looks cleaner.

4. Comparing Merge and Rebase

Merge preserves the complete development history and clearly shows branch structure, which is useful for understanding when and how features were integrated, but it can create many merge commits that clutter the graph.

Rebase creates a linear history that is easier to read and review, but it rewrites commit hashes, which can cause conflicts in collaborative environments and should be used with caution.