2. UNDO

REWRITING HISTORY

⇒ Ammended commits are new commits

⇒ Old commit is completely removed from history

EXAMPLES

CRAP, I forgot to branch!

 $ git reset --soft HEAD^

* Changes are unstaged but

still there

Urgh, I need to undo last 3 commits!

 $ git reset HEAD~2

* Changes are unstaged but

still there, check git reflog HEAD starts at 0

OOps, I did not mean to Do that!

 $ git reset path/to/filename

* Restores the file to the latest version

in HEAD, changes are preserved

OOps I did not mean to DELETE that!

 $ git checkout path/to/filename

* Restores the file to the latest version

in HEAD, changes are dropped

Aha, I found what introduced the bug!

 $ git revert commit-hash

* Reverts a commit with another commit,

doesn't amend history.

OOPS, I didn't mean to commit yet!

 $ git commit --amend

OOPS, I forgot to add a file!

 $ git add filename

 $ git commit --amend --no-edit

1

2

⇒ Moving a branch onto a new base commit 

⇒ Rebasing onto master will take all commits from master and apply your branch commits on top one by one

WHAT IS A REBASE?

 $ git rebase -i master

 $ git rebase -i master

⇒ Let's squash commit 2 into 1

⇒ Let's edit commit 3

Pick, Squash & Edit

Squashing

Squashing: Amending the message

Squashing: save

Edited message 3

Continue rebase

Done!

Enable RERERE

 $ git config --global rerere.enabled true

⇒ reuse recorded solution

⇒ no need to deal with the same rebase conflicts again!

Git reflog

 $ git reflog

⇒ reflog = referene log

⇒ records when the tips of branches and other references were updated in the local repository.

Takeaways

⇒ never rebase after merge

⇒ after code is shared use merge not rebase

⇒ only rebase before pushing

⇒ amend and undo things locally only before pushing

Thanks!