Why rebasing creates linear history in Git - See It in Action

Why Rebasing Creates Linear History

📖 Scenario: You are working on a project with a friend. Both of you make changes in separate branches. You want to combine your changes in a clean way so the history looks simple and easy to follow.

🎯 Goal: Learn how to use git rebase to create a linear commit history instead of a branching one.

📋 What You'll Learn

Create a new branch called feature from main

Make two commits on feature branch

Switch back to main and make one commit

Use git rebase main on feature branch to apply changes linearly

Show the commit history with git log --oneline --graph

💡 Why This Matters

🌍 Real World

Developers often work on features in separate branches. Rebasing helps keep the project history clean and linear, making it easier to understand what changes were made and when.

💼 Career

Understanding rebasing is important for collaboration in teams using Git. It helps avoid messy histories and simplifies code reviews and debugging.

1

Create initial branches and commits

Create a new branch called feature from main. Then make two commits on feature branch with commit messages feat: add first feature and feat: add second feature. Use touch and git add to create files feature1.txt and feature2.txt respectively.

Git

# Create and switch to feature branch
# Create feature1.txt and commit with message 'feat: add first feature'
# Create feature2.txt and commit with message 'feat: add second feature'

Hint

Use git checkout -b feature to create and switch to the feature branch.

Use touch to create files and git add to stage them before committing.

2

Make a commit on main branch

Switch back to main branch. Create a file called hotfix.txt and commit it with the message fix: hotfix on main.

Git

git checkout -b feature

touch feature1.txt
 git add feature1.txt
 git commit -m "feat: add first feature"

touch feature2.txt
 git add feature2.txt
 git commit -m "feat: add second feature"

# Switch to main branch and create hotfix.txt
# Commit with message 'fix: hotfix on main'
# Your code here

Hint

Use git checkout main to switch back to main branch.

Create the file and commit it as before.

3

Rebase feature branch onto main

Switch back to feature branch. Use git rebase main to move the feature branch commits on top of the latest main branch commit.

Git

git checkout -b feature

touch feature1.txt
 git add feature1.txt
 git commit -m "feat: add first feature"

touch feature2.txt
 git add feature2.txt
 git commit -m "feat: add second feature"

git checkout main

touch hotfix.txt
 git add hotfix.txt
 git commit -m "fix: hotfix on main"

git checkout feature
# Rebase feature branch onto main
# Your code here

Hint

Use git checkout feature to switch to feature branch.

Then run git rebase main to replay feature commits on top of main.

4

Show the linear commit history

Run git log --oneline --graph to display the commit history. Notice how the commits from feature branch appear in a straight line after the main branch commit.

Git

git checkout -b feature

touch feature1.txt
 git add feature1.txt
 git commit -m "feat: add first feature"

touch feature2.txt
 git add feature2.txt
 git commit -m "feat: add second feature"

git checkout main

touch hotfix.txt
 git add hotfix.txt
 git commit -m "fix: hotfix on main"

git checkout feature

git rebase main

# Show the commit history graph
# Your code here

Hint

Use git log --oneline --graph to see the commit history as a graph.

You should see a straight line of commits after rebasing.

Practice

1. What is the main reason rebasing creates a linear history in Git?

easy

A. It creates a new branch automatically

B. It merges all branches into one commit

C. It deletes all previous commits

D. It moves your commits on top of the latest commit from the target branch

Solution

1. Step 1: Understand what rebasing does

   Rebasing takes your commits and places them on top of another branch's latest commit, replaying them in order.

2. Step 2: Effect on commit history

   This action removes the branching structure by making your commits appear as if they were made after the latest commit on the target branch, creating a straight line.

3. Final Answer:

   It moves your commits on top of the latest commit from the target branch -> Option D

4. Quick Check:

   Rebase = replay commits on top [OK]

Hint: Rebase replays commits on latest branch commit [OK]

Common Mistakes:

• Thinking rebase merges commits into one
• Believing rebase deletes old commits
• Confusing rebase with branch creation

2. Which Git command syntax correctly rebases the current branch onto main?

easy

A. git merge main

B. git rebase main

C. git rebase -m main

D. git checkout main rebase

Solution

1. Step 1: Identify the correct rebase command

   The correct syntax to rebase the current branch onto main is git rebase main.

2. Step 2: Check other options for errors

   git merge main merges instead of rebasing; git rebase -m main is invalid syntax; git checkout main rebase is not a valid command.

3. Final Answer:

   git rebase main -> Option B

4. Quick Check:

   Rebase syntax = git rebase branch [OK]

Hint: Use 'git rebase branchname' to rebase [OK]

Common Mistakes:

• Using merge instead of rebase
• Adding invalid flags like -m
• Combining checkout and rebase incorrectly

3. Given this commit history:

main: A --- B --- C
feature: A --- B --- D --- E

After running git rebase main on feature, what will the new commit history look like?

medium

A. main: A --- B --- Cfeature: A --- B --- C --- D' --- E'

B. main: A --- B --- Cfeature: D --- E

C. main: A --- B --- C --- D --- Efeature: A --- B --- C --- D --- E

D. main: A --- B --- Cfeature: A --- B --- D --- E

Solution

1. Step 1: Understand rebase effect on commits

   Rebasing feature onto main moves commits D and E to be based on C, replaying them as new commits D' and E'.

2. Step 2: Visualize new commit history

   The main branch remains unchanged. The feature branch now appears as if commits D' and E' were made after C, creating a linear history.

3. Final Answer:

   main: A --- B --- C
   feature: A --- B --- C --- D' --- E' -> Option A

4. Quick Check:

   Rebase = replay commits on main tip [OK]

Hint: Rebase replays commits after target branch tip [OK]

Common Mistakes:

• Assuming commits stay unchanged
• Thinking rebase merges commits
• Ignoring that rebased commits get new IDs

4. You tried to rebase your branch but got a conflict error. What is the best way to fix this and continue the rebase?

medium

A. Abort the rebase and start over with git rebase --abort

B. Run git merge --continue to resolve conflicts

C. Fix the conflicts manually, then run git rebase --continue

D. Delete the branch and create a new one

Solution

1. Step 1: Understand rebase conflict handling

   When a conflict occurs during rebase, Git pauses and lets you fix conflicts manually in the files.

2. Step 2: Continue rebase after fixing conflicts

   After resolving conflicts, you must run git rebase --continue to proceed with the rebase process.

3. Final Answer:

   Fix the conflicts manually, then run git rebase --continue -> Option C

4. Quick Check:

   Fix conflicts + git rebase --continue [OK]

Hint: Fix conflicts then run 'git rebase --continue' [OK]

Common Mistakes:

• Using merge commands during rebase
• Aborting instead of continuing after fix
• Deleting branch unnecessarily

5. You have two feature branches, feature1 and feature2, both branched from main. feature1 was rebased onto main and pushed. Now you want to rebase feature2 onto feature1. What is the main benefit of this approach?

hard

A. It creates a linear history combining both features without merge commits

B. It deletes feature1 branch automatically

C. It merges feature2 into main directly

D. It resets feature2 to main ignoring feature1

Solution

1. Step 1: Understand rebasing one feature branch onto another

   Rebasing feature2 onto feature1 places feature2's commits on top of feature1, making the history linear.

2. Step 2: Benefit of linear history

   This avoids merge commits and shows a clear sequence of changes, making history easier to read and understand.

3. Final Answer:

   It creates a linear history combining both features without merge commits -> Option A

4. Quick Check:

   Rebase feature2 on feature1 = linear combined history [OK]

Hint: Rebase feature2 on feature1 for clean linear history [OK]

Common Mistakes:

• Thinking rebasing deletes branches
• Confusing rebase with merge into main
• Ignoring the order of branches in rebase