Axosoft ™ GitKraken is an open source command-line interface that is according to their website, cross-platform and made by devs for devs. It was built to for working with the version control system Git. That includes cloning, pushing, pulling, branching, rebasing, merging all in a quick to learn and beautiful interface.
It's in active development and will work consistently, making it an ally when doing professional work.
Related: How To Install GitKraken on Ubuntu