Editing commit messages with rebase in Git - Mini Project: Build & Apply

Editing commit messages with rebase

📖 Scenario: You have made several commits in your local Git repository. Now, you want to improve the commit messages to make them clearer and more descriptive before sharing your work with your team.

🎯 Goal: Learn how to edit commit messages of previous commits using Git's interactive rebase feature.

📋 What You'll Learn

Have a Git repository with at least three commits

Use Git commands to edit commit messages

Understand how to use interactive rebase safely

💡 Why This Matters

🌍 Real World

Improving commit messages helps your team understand changes clearly and keeps project history clean.

💼 Career

Editing commit messages is a common task for developers and DevOps engineers to maintain professional and readable version control history.

1

Create three commits with specific messages

Create three commits in your Git repository with these exact commit messages in order: Initial commit, Add README file, and Fix typo in README. Use git commit -m to set the messages.

Git

# Create three commits with the exact messages
# Your code here

Hint

Use git commit -m "message" to create commits with the exact messages.

2

Start interactive rebase to edit commit messages

Run the Git command to start an interactive rebase for the last three commits using git rebase -i HEAD~3.

Git

git init

echo "Project start" > file.txt
git add file.txt
git commit -m "Initial commit"

echo "# Project README" > README.md
git add README.md
git commit -m "Add README file"

sed -i 's/README/Readme/' README.md
git add README.md
git commit -m "Fix typo in README"

# Start interactive rebase for last 3 commits
# Your code here

Hint

Use git rebase -i HEAD~3 to start editing the last three commits.

3

Change commit messages to new ones in the rebase editor

In the interactive rebase editor, change the word pick to reword for all three commits to edit their messages. Save and close the editor to proceed.

Git

git init

echo "Project start" > file.txt
git add file.txt
git commit -m "Initial commit"

echo "# Project README" > README.md
git add README.md
git commit -m "Add README file"

sed -i 's/README/Readme/' README.md
git add README.md
git commit -m "Fix typo in README"

git rebase -i HEAD~3

# In the editor, replace 'pick' with 'reword' for all commits
# Your code here

Hint

Change pick to reword for each commit line in the editor to edit messages.

4

Edit commit messages and verify final log

For each commit message prompt during the rebase, change the messages to these exact new messages in order: Setup project files, Add project README, and Correct README typo. After finishing, run git log --oneline and print the output.

Git

git init

echo "Project start" > file.txt
git add file.txt
git commit -m "Initial commit"

echo "# Project README" > README.md
git add README.md
git commit -m "Add README file"

sed -i 's/README/Readme/' README.md
git add README.md
git commit -m "Fix typo in README"

git rebase -i HEAD~3

# Edit commit messages to:
# "Setup project files"
# "Add project README"
# "Correct README typo"
# Then run git log --oneline and print the output
# Your code here

Hint

When prompted, replace each commit message with the new exact message. Then run git log --oneline to see the updated commits.

Practice

1. What does the command git rebase -i HEAD~3 allow you to do?

easy

A. Delete the last 3 commits permanently

B. View the commit history without changes

C. Create 3 new commits automatically

D. Interactively edit the last 3 commits, including their messages

Solution

1. Step 1: Understand the command purpose

   git rebase -i HEAD~3 opens an interactive editor for the last 3 commits.

2. Step 2: Recognize the interactive editing feature

   It allows changing commit messages, reordering, or squashing commits.

3. Final Answer:

   Interactively edit the last 3 commits, including their messages -> Option D

4. Quick Check:

   Interactive rebase edits commits [OK]

Hint: Use -i with HEAD~N to edit last N commits [OK]

Common Mistakes:

• Thinking it deletes commits
• Assuming it creates new commits
• Confusing it with git log

2. Which line correctly changes a commit action to edit its message during an interactive rebase?

easy

A. reword abc123 Update README with new info

B. pick abc123 Fix typo in README

C. edit abc123 Add new feature

D. delete abc123 Remove unused file

Solution

1. Step 1: Identify the correct keyword for editing messages

   In interactive rebase, reword lets you change the commit message only.

2. Step 2: Compare options

   edit pauses for full commit changes, pick keeps commit as is, delete is invalid here.

3. Final Answer:

   reword abc123 Update README with new info -> Option A

4. Quick Check:

   Use 'reword' to edit message only [OK]

Hint: Change 'pick' to 'reword' to edit commit messages [OK]

Common Mistakes:

• Using 'edit' when only message change is needed
• Leaving 'pick' unchanged
• Using invalid 'delete' keyword

3. After running git rebase -i HEAD~2 and changing the first commit's action from pick to reword, what happens next?

medium

A. Git deletes the first commit

B. Git opens an editor to change the first commit message, then continues rebase

C. Git aborts the rebase immediately

D. Git merges the two commits automatically

Solution

1. Step 1: Understand 'reword' effect during rebase

   Changing 'pick' to 'reword' tells Git to pause and open the commit message editor for that commit.

2. Step 2: Follow rebase process

   After editing the message, Git continues applying remaining commits automatically.

3. Final Answer:

   Git opens an editor to change the first commit message, then continues rebase -> Option B

4. Quick Check:

   'reword' opens message editor [OK]

Hint: Reword pauses to edit message, then continues [OK]

Common Mistakes:

• Thinking rebase aborts on reword
• Assuming commits get deleted
• Expecting automatic merge without editing

4. You ran git rebase -i HEAD~2 and changed 'pick' to 'reword' for the second commit, but after saving, Git shows an error: error: could not apply abc123. What is the likely cause?

medium

A. You used 'reword' instead of 'edit'

B. You forgot to save the commit message editor

C. There is a conflict applying the second commit during rebase

D. The commit hash is invalid

Solution

1. Step 1: Understand the error message

   error: could not apply abc123 means Git failed to apply that commit, usually due to conflicts.

2. Step 2: Relate to rebase process

   During rebase, conflicts can happen if changes overlap; you must resolve them manually.

3. Final Answer:

   There is a conflict applying the second commit during rebase -> Option C

4. Quick Check:

   Apply error = conflict during rebase [OK]

Hint: Apply errors usually mean conflicts to resolve [OK]

Common Mistakes:

• Assuming 'reword' causes error by itself
• Ignoring conflict resolution step
• Thinking commit hash is wrong

5. You want to edit the commit messages of the last 4 commits but keep the commit content unchanged. Which sequence of commands and actions is correct?

hard

A. Run git rebase -i HEAD~4, change all 'pick' to 'reword', save, then edit each message when prompted

B. Run git commit --amend four times in a row

C. Run git reset --soft HEAD~4 and recommit with new messages

D. Run git rebase -i HEAD~4, change 'pick' to 'edit', then change messages and contents

Solution

1. Step 1: Choose the right rebase command

   git rebase -i HEAD~4 opens interactive rebase for last 4 commits.

2. Step 2: Use 'reword' to edit messages only

   Changing 'pick' to 'reword' lets you edit commit messages without changing content.

3. Step 3: Save and edit messages when prompted

   Git opens editor for each commit message in turn; you update and save them.

4. Final Answer:

   Run git rebase -i HEAD~4, change all 'pick' to 'reword', save, then edit each message when prompted -> Option A

5. Quick Check:

   Use 'reword' in interactive rebase for message edits only [OK]

Hint: Use 'reword' for messages, 'edit' for content changes [OK]

Common Mistakes:

• Using commit --amend repeatedly instead of rebase
• Resetting and recommitting loses history
• Using 'edit' when only message change needed