keychain command line access

If you're using the osxkeychain github credentials manager, here's a command to retrieve your github password from the command line:

security find-internet-password -w -s 'github.com'

Here's how to add an API secret to your keychain:

security add-generic-password -s '<service name>' -a '<account name>' -w '<password>'

And how to retrieve it:

security find-generic-password -w -s '<service name>'

You can add -a <account name> to that if the service name is not enough to specify the password exactly, but find works if there's only one matching service.