Use the ssh protocol instead of http/https.
Using http/https you will have to type your password every time you have to "talk" to the server.
Using ssh will use the ssh keys and you will not have to type in username password every time.
git clone [email protected]:owner/repo.git
Permission denied (publickey)
You get this error since you don't have ssh keys on any of your platforms.
Set the keys, add them to your account and you are all set to go.
Create ssh keys
# create the key pair.
ssh-keygen -t rsa
# echo the key (pub) to the screen and copy it to clipboard
cat ~/.ssh/id_rsa.pub
Add the keys to your bitbucket account

Note:
Repeat this step on each machine you need to connect to your account or copy the same keys to all your machines. Both ways will work.
git version 1.7.12.4 (Apple Git-37)On Ubuntu1.9.1