modifications for mac and bsd date

I commented out your original lines and made modifications for Mac:

- changed `espeak` to `say`
- changed the `date` commands to be compatible with BSD date

Unrelated, but is there a reason for putting default options in the script itself? Why not just have `getopts` set option variables to true? User can always effectively create defaults by creating an alias for the specific set of options he/she wants.