how do I continuously do a ps auxw on OSX?

If you have macports available (or possibly homebrew or a similar environment) you can use watch to print the output of the command every second:

 watch -n 1 ps auxw

An alternative is to use glances, which is also available through macports.

You can indeed use watch for this. Alternatives are

1. top and htop: these display processes in continuously updating windows.

2. Use the shell

   while true; do ps auxw; sleep 1; done
   

3. Use strace on Linux or ktrace on OSX.