Handy Git aliases

Posted on Fri 06 January 2023 in hints-and-kinks • 2 min read

I use Git on a practically daily basis, and although it comes with just about everything including the proverbial kitchen sink, there are a few bits of functionality that I only wish it had. Luckily, Git’s functionality is almost indefinitely extensible via the use of aliases.

So, here are some that I define in my ~/.gitconfig file, with a brief explanation of what they’re good for:

List branches by their date of last modification

  recent = branch --sort=-committerdate --format=\"%(committerdate:relative)%09%(refname:short)\"

I frequently have a pretty large number of topic branches that I work on, plus ones that I pull in from other people’s remotes for local review. So it’s helpful to know which branches in my checkout were most recently updated, and I can run git recent to do that.

Delete old topic branches that have been merged

  delete-merged-branches = !git branch --merged | grep -Ev '(main|master)' | xargs -prn1 git branch -d

I create a topic branch for everything that needs to be reviewed and merged to main at some point. That means it’s not unheard of that I create dozens of them each month, and they quickly accumulate. If I did not regularly prune old topic branches, my Git checkouts would become unmanageable pretty quickly.

So, I use my git delete-merged-branches command to remove those local branches that are fully merged to main.

Find the origin of a branch point

    oldest-ancestor = !bash -c 'diff -u <(git rev-list --first-parent \"${1:-main}\") <(git rev-list --first-parent \"${2:-HEAD}\") | sed -ne \"s/^ //p\" | head -1' -

Sometimes I create a topic branch off main, then add oodles of commits on it. At the same time, more commits land on main, and eventually I forget which commit I based my branch on.

Then, I can use git oldest-ancestor to retrace my branch point, like so:

  • git oldest-ancestor foo bar: find out at which commit bar branched off foo.
  • git oldest-ancestor foo: find out at which commit the currently checked-out branch branched off foo.
  • git oldest-ancestor: find out at which commit the currently checked-out branch branched off main.

I seem to recall I learned this trick from a Stack Overflow discussion, which I can’t find anymore. What I have found is a similar implementation from Lee Dohm that is MIT licensed: git-oldest-ancestor.

Fix trailing whitespace

  fixws = !git diff-index --check --cached HEAD -- | sed /^[+-]/d | sed -r s/:[0-9]+:.*// | uniq | xargs sed -e s/[[:space:]]*$// -i

I usually want to avoid committing changes with extraneous whitespace, and if I enable the default pre-commit script that lives in a .git/hooks directory by dropping .sample off its filename, Git will even enforce this as a pre-commit rule.

So what I do is this:

  • I try git commit.
  • Git complains about trailing whitespace.
  • I run git fixws, and repeat my git commit command.