Regarding gitflow-avh in Ubuntu with manual git installation, I wanted to let people know that, in Ubuntu, if you installed gitflow-avh using the command
sudo apt-get install git-flow
and then manually installed git (for me it was git version 2.13), you may have come across git flow not being a command anymore.
Well, it turns out that the default ubuntu git-flow installs for the git-core library, and not for the manually installed git. All you need to do is uninstall git flow
sudo apt-get remove git-flow
manually install git flow by cloning the git repo and running make install.
https://github.com/petervanderdoes/gitflow-avh/wiki/Installing-manuallyThis installs it into the correct directory (/usr/local) instead of the git-core directory(/usr/lib/git-core/).