Switch user from bitbucket to github

I work for a team that stores its repositories on Bitbucket, so I have an account there.

Now I’m starting to work simultaneously for another team that stores its repositories on GitHub.

I have a couple of questions:

1. Since on both Bitbucket and GitHub they use Git to manage their repository, can I use the old account from Bitbucket on GitHub as well, or do I have to open a new one in GitHub? If it’s possible to only use one account please tell me the instructions how to do that.
2. In case I need to open a new account on GitHub, how can I switch between the accounts on my computer? I use Ubuntu 14 OS.

Answer

1. You cannot log into GitHub with your Bitbucket account. You used to be able and currently still are able to log into your Bitbucket account with your GitHub account, but this support is phasing out and shouldn’t be used anymore.
2. You don’t need to switch. The repositories each have the remotes defined where you push them to. Those remotes are the URL including the server. If you add your SSH key to both accounts, you then can simply push to both, without the need to do anything special to switch accounts.