Rebase vs merge mental model in Git - CLI Comparison

Introduction

When working with Git, you often need to combine changes from different branches. Rebase and merge are two ways to do this, but they work differently. Understanding when to use each helps keep your project history clean and easy to follow.

When you want to update your feature branch with the latest changes from the main branch before finishing your work

When you want to combine changes from two branches but keep a clear history of how the work was done

When you want to avoid creating extra merge commits to keep the project history linear

When you want to preserve the exact history of how branches were combined, including merge points

When you want to prepare your branch for a clean integration into the main branch

Commands

Switch to your feature branch where you want to integrate changes from the main branch.

Terminal

git checkout feature-branch

Expected Output

Switched to branch 'feature-branch'

Rebase your feature branch on top of the latest main branch commits. This moves your changes to the tip of main, creating a linear history.

Terminal

git rebase main

Expected Output

First, rewinding head to replay your work on top of it...

Applying: Add new feature

Switch back to the main branch to prepare for merging your feature branch.

Terminal

git checkout main

Expected Output

Switched to branch 'main'

Merge the feature branch into main. This creates a merge commit that shows the branches were combined.

Terminal

git merge feature-branch

Expected Output

Updating 1a2b3c4..5d6e7f8

Fast-forward

 file.txt | 2 ++

 1 file changed, 2 insertions(+)

View the commit history graph to see the difference between rebased and merged commits.

Terminal

git log --oneline --graph --all

Expected Output

* 5d6e7f8 (HEAD -> main) Add new feature

* 1a2b3c4 Previous commit on main

Key Concept

If you remember nothing else, remember: rebase rewrites history to create a straight line of commits, while merge preserves the branch history with a merge commit.

Common Mistakes

Using rebase on a branch that others are also using

Rebasing rewrites history, which can confuse others and cause conflicts when they try to update their branches.

Use rebase only on local or private branches before sharing, and use merge for shared branches.

Merging without updating the feature branch first

This can create unnecessary conflicts or merge commits that could have been avoided.

Update your feature branch with rebase or merge from main before merging it back.

Summary

Use 'git rebase main' on your feature branch to apply your changes on top of the latest main branch commits, creating a linear history.

Use 'git merge feature-branch' on main to combine branches and preserve the full branch history with a merge commit.

Rebase rewrites commit history and should be used carefully, especially on shared branches.