Git for Git Users

Commit messages

• First line: Imperative subject line (max. 50 chars)
• One free line
• Other relevant information, reasoning, explanations, etc.

Pulling

• When the server has changes unrelated to yours: git pull --rebase
  • Make this the default: git config --bool pull.rebase true
  • In this case, git pull --merge can be used to restore previous behavior.
• When the server has changes and you do not: git pull --ff-only
• Otherwise: git pull (Works always, but sometimes not as pretty)

Other tricks

• git reset --soft HEAD^ moves changes from the last commit back to the index so that they can be edited.
• Follow up with git commit -c ORIG_HEAD to re-commit afterwards.

Undo things

Revert

• If you want to undo changes that have been pushed, you can revert them
• git revert HEAD reverts the latest commit
• git revert <commit> reverts one commit by hash

Amend

• If you want to change something about your latest (unpushed!!) commit, you can amend it
• Make your change on the index, then git commit --amend
• Can also be used to change the commit message (interactively or with -m)

Reflog

• If you want to undo things locally (meaning not pushed anywhere), you can use the reflog
• This can also undo an undo change, or “redo” the change
• git reflog shows you what recent actions git has tracked
  • Anything that changes HEAD: checkout, switch, merge, rebase, reset, commit, etc.
• The most recent entry HEAD@{0] is the current state
• You can use these refs in any command that accepts a ref. Example: git reset --hard 'HEAD@{2}' undoes the last two actions
  • This will add a new entry into the reflog, and can be undone with another reset.
• You can also use dates instead of numbers, e.g. git reset --hard '@{yesterday}' undoes everything done locally today

Combining commits

Scenario: you want to combine changes from multiple commits into one and they have not been pushed.

Option 1: preserving all commit messages

• git reset --hard HEAD~5 undoes the last 5 commits
• git merge --squash 'HEAD@{1}' squash-merges those 5 commits back into linear history
• git commit creates the actual squashed commit
  • Message will open in editor with all commit messages combined

Option 2: new commit message

• git reset --soft HEAD~5 undoes the last 5 commits, but keeps the changes in the working directory and index
• git commit creates the squashed commit and allows you to enter a new message

Option 3: flexibility

• git rebase -i HEAD~5 will begin an interactive rebase session with the last 5 commits
• If unsure how many commits can be rebased safely, you can use git rebase -i @{push} to only rebase unpushed commits
• Your configured editor will open with the rebase todo-list
• You can reorder lines to reorder commits
• You can replace the word pick on any line with squash to combine them and concatenate the commit messages
• Analogously, fixup combines commits but only keeps the first (topmost) commit’s message

Reordering commits

• git rebase -i HEAD~5 will begin an interactive rebase session with the last 5 commits
• Your configured editor will open with the rebase todo-list
• You can reorder lines to reorder commits