date -d is different from Linux to Mac

familiar with:

date -d '1 hour ago'

well, it will work on the Linux command line, but no such luck on the Mac

here is the code you need if your script is to work on both OSes:

OS=`uname -a`
if [[ $OS == Darwin* ]]
then
    TODAY=`date -v-1H +"%Y-%m-%d.%H"`
else
    TODAY=`date -d '1 hour ago' +"%Y-%m-%d.%H"`
fi