Always use passwordless login.

A command should be executed on a remote server via ssh [remote server] [command path]. Shell commands should be executed on a remote server via something like echo [script] | ssh [remote server] "/usr/bin/sh" in order to control, which shell is being used. Alternatively, use something like ssh [remote server] "/usr/bin/sh" << EOF [script] EOF, when inline multi line scripts are considered.