All the useful Git commands I've found (mostly from StackOverflow), in one convenient reference.

git-cheat.md

Branch from an old commit

git branch branchname ref

where ref is either a sha (abcd123) or a pointer HEAD@{5}

Undo a commit

git reset HEAD~1

--hard undoes changes to files, --soft leaves the index unchanged

Undo add

git reset HEAD file

Bonus: Undo git add . with git reset (but just don't do git add . in the first place).

Pull in changes from original repo to your fork

[git remote add upstream https://github.com/otheruser/repo.git] # First time only
git fetch upstream
[git checkout master] # If not on master already
git merge upstream/master

Restore an old file

git rev-list -n 1 HEAD -- file_path
git checkout deleting_commit^ -- file_path

Undo changes since last commit

git reset HEAD --hard
git clean -fd

Apply commits from one branch to another

git reflog              # View a list of commit SHAs
git cherry-pick abcd123 # Apply the commit with that SHA to the current branch

Edit a commit message

git commit --amend -m "New commit message"

Add files to an existing commit

git add path/to/forgotten.file
git commit --amend –C HEAD

List all files tracked by Git

git ls-tree --full-tree -r HEAD

Merge in changes to one file in another branch

# While on the branch you want to merge to
git checkout --patch other_branch file

Diff two branches

git diff --name-status branch1..branch2

Delete branches

• Local: git branch -D branchname
• Remote: git push origin --delete branchname

Delete first commit: git update-ref -d HEAD