Answer by Olivier Refalo for How do I get the current branch name in Git?

Well simple enough, I got it in a one liner (bash)

git branch | sed -n '/\* /s///p'

(credit: Limited Atonement)

And while I am there, the one liner to get the remote tracking branch (if any)

git rev-parse --symbolic-full-name --abbrev-ref @{u}