With the latest releases of IBM i (I think 7.1 and following) it is possible to install git on IBM i. There are some articles covering how to install it and Aaron Bartell even wrote an article on how to use it with github.com .
I had some problems when I first tried to use git with bitbucket.org .
One of the first problems is: Which shell should I use? QShell, Bash in PASE, connect via SSH and use Bash?
PASE and SSH seems to work. But never use QShell. QShell behaves most of the time like Bash in PASE but it isn't and there will be some problems. I had my best experience with PASE.
You will need some SSH keys to communicate securely with bitbucket. Key generation is really straightforward.
ssh-keygen -t rsa -f .ssh/id_rsa
You may encounter this error when you try to communicate with the git server. You need to add the SSH key of the domain to your known_hosts.
ssh-keyscan -t rsa github.com >> ~/.ssh/known_hosts
Seems there is some limitation on resources. My mistake was to have started the QShell instead of the shell in PASE. So moving to PASE solved this problem for me.
To shorten the output for the status of the git repository use the following alias:
git config --global alias.shorty 'status --short --branch'