How can I perform a `git pull` without re-entering my SSH password?

Have a look at this link https://help.github.com/articles/working-with-ssh-key-passphrases/

But I don’t want to enter a long passphrase every time I use the key!

Neither do I! Thankfully, there’s a nifty little tool called ssh-agent that can save your passphrase securely so you don’t have to re-enter it. If you’re on OSX Leopard or later your keys can be saved in the system’s keychain to make your life even easier. Most linux installations will automatically start ssh-agent for you when you log in.

Try this:

git config credential.helper store

You'll have to enter your password once, after that it is stored in a folder inside root.

As comments pointed out, This does NOT work for SSH passwords, only for HTTPS passwords.

I enabled the password caching as described here:

https://help.github.com/articles/caching-your-github-password-in-git/#platform-linux

To cache the password for a month:

git config --global credential.helper 'cache --timeout=2628000'