Installation instructions

- Install Docker Desktop for Mac.

    https://download.docker.com/mac/stable/Docker.dmg

  Start the app.  If it is running, the docker icon (a whale stacked with
  container boxes) should be present on the top menu bar on the right hand
  side.

- Open a terminal window and type the following at the command prompt ::

    Kens-MBP:~ $ docker pull tehatanlgov/ptolemy:latest

  This downloads the ptolemy container from docker hub.  You need do this only
  once. List downloaded containers with ::

    Kens-MBP:~ $ docker images

- Make the ptolemy script executable by typing ::

    Kens-MBP:~ $ chmod 755 /path/to/ptolemy

  where /path/to/ptolemy is the full path to where you saved the file.  Eg, if
  you saved it to your home directory, then it would be ~/ptolemy.  To run
  ptolemy, type ::

    Kens-MBP:~ $ /path/to/ptolemy < something.in > something.out

  Tip: I suggest you save the ptolemy script to your home bin directory. Make
  one if you don't have one and add the bin directory path to your PATH
  environment variable. Ask if you need instructions on how to do this. After
  you do this, then all you need to say is ::

    Kens-MBP:~ $ ptolemy < another.in  > another.out