You pose a very general question, but your example is just about the "restarting" notification that you get from breakpoint commands that contain "continue" commands somewhere in them.
For that specific issue, though there is no such thing yet, it would be straightforward to add a --quiet flag to the "breakpoint command add" command. File a bug either with the lldb bugzilla or bugreporter.apple.com or if you are feeling adventurous check out the lldb sources and have at it yourself. A patch to that effect would be gladly accepted.
If there are other places where you feel the command output is too chatty, ask about them individually.