This guide explains how to modify or combine commits that have already been created. These are powerful tools for keeping your Git history clean and readable.

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This is the perfect tool when you've made a mistake in the message of your most recent commit.

• You made a typo in the commit message.
• You forgot to add a ticket ID (e.g., JIRA-123).
• You want to add a very small code change to the previous commit instead of creating a new one.

1. Step 1: Amend the Commit Locally

Run the following command. This will open your default text editor to let you change the message.

git commit --amend

  Alternatively, to change the message directly from the command line without opening the editor:

git commit --amend -m "feat(auth): [JIRA-123] Add user login endpoint"

1. Step 2: Push the Changes to the Server

Because you have changed a commit that already exists on the remote server, you must force the update. Always use the safer `–force-with-lease` option.

git push --force-with-lease origin <your-branch-name>

--force-with-lease

--force

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“Squashing” means to combine several smaller, sequential commits into a single, logical commit.

• You have made several small, incremental commits (e.g., “WIP”, “Fix typo”, “Add test”) and want to present them as one coherent feature.
• You want to clean up your branch's history before creating a Pull/Merge Request, making it easier for others to review.

We will use the interactive rebase command (

git rebase -i

).

1. Step 1: Start the Interactive Rebase

If you want to combine the last 3 commits, run the following command:

git rebase -i HEAD~3

  (Replace `3` with the number of commits you want to work with).

1. Step 2: Choose Your Actions

A text editor will open with a list of the commits you selected, with the oldest one first.

pick 1a2b3c4 feat: Add initial login form structure
pick 5d6e7f8 fix: Correct validation logic on login
pick 9g8h7i6 refactor: Clean up login service

  To combine them, keep the first commit with **<code>pick</code>** and change the action for all subsequent commits to **<code>squash</code>** (or the shorthand **<code>s</code>**).

pick 1a2b3c4 feat: Add initial login form structure
s 5d6e7f8 fix: Correct validation logic on login
s 9g8h7i6 refactor: Clean up login service

  Now, save and exit the editor.

1. Step 3: Write the New, Combined Commit Message

Git will open another text editor, containing the messages from all the commits you are squashing. Delete the old text and write a single, clear message that describes the combined change.

feat(auth): [JIRA-123] Implement user login functionality

- Adds the HTML structure and styling for the login form.
- Implements client-side and server-side validation for user credentials.
- Refactors the authentication service for better clarity and performance.

  Save and exit the editor.

1. Step 4: Push the Changes to the Server

Your local history has now been rewritten. Update the remote server using the safe force-push command:

git push --force-with-lease origin <your-branch-name>

• In the Log Messages window, right-click on the commit that comes before the ones you want to combine.
• From the context menu, choose <code>Rebase “<your-branch-name>” onto this…</code>.
• A “Rebase” window will appear. For each commit you want to combine (except the first one), change its action from “Pick” to <code>Squash</code>.
• Click Start Rebase. You will then be prompted to edit the final commit message.
• After the rebase is complete, Push your changes, making sure to check the force option (preferably one that mentions “with lease”).