Git Concepts - Second Day

1- Undoing Commits (reset vs. revert)

git reset - Undo commits and move the branch pointer

Git reset is used to undo commits. It comes in three types:

• --soft → Keeps changes in Staging (index).
• --mixed → Keeps changes in Working Directory (default).
• --hard → Deletes commits and changes permanently.

Example:

git reset --soft HEAD~1  # Undo last commit but keep changes staged
git reset --mixed HEAD~1  # Undo last commit and unstage changes
git reset --hard HEAD~1  # Undo commit and delete changes permanently! ⚠️

git revert - Undo a commit without deleting history

Unlike reset, revert creates a new commit that cancels the changes of a previous commit.

Example:

git revert HEAD  # Reverts the last commit with a new commit
git revert <commit-hash>  # Reverts a specific commit

When to use each?

• Use reset when working locally and want to completely remove a commit.
• Use revert if the commit has already been pushed and you want to keep history clean.

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2- Stashing - Saving Changes Temporarily

git stash is used to save uncommitted changes temporarily without committing them.

Example:

git stash          # Save changes and get a clean working directory  
git stash pop      # Retrieve the latest stash and remove it  
git stash apply    # Retrieve the latest stash without removing it  
git stash list     # Show all saved stashes  
git stash clear    # Delete all stashes  

When to use stash?

• When working on a feature branch and need to switch to another branch without committing.
• When testing something quickly but don’t want to commit unfinished changes.

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3- Rebasing - Merging Branches in a Linear Way

git rebase moves commits from one branch to another without creating extra merge commits.

Example:

git checkout feature-branch  
git rebase main  # Moves feature-branch commits on top of main  

When to use rebase?

• To keep commit history clean and linear instead of multiple merge commits.
• To update a feature branch with the latest changes from main.

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4- Interactive Rebasing - Editing Commit History

git rebase -i allows you to edit, reorder, squash, or delete commits interactively.

Example:

git rebase -i HEAD~3  # Edit last 3 commits  

Inside the editor, you can:

• pick → Keep commit as is
• reword → Change commit message
• edit → Modify commit contents
• squash → Merge commits
• drop → Delete commit When to use interactive rebasing?
• To clean up messy commit history before pushing.
• To combine multiple small commits into one.

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