[magick-users] Can we read the ouptu of the 'compare' command and make a 'Pass/Fail' answer from it?

[Fred Weinhaus]

compare -metric rmse input.png output.png null:

will give you the rmse difference value to the terminal. you can set 
your own threshold for rmse value to decide if it is pass or fail or 
put the result in string variable and do further testing

str=`compare -metric rmse input.png output.png null: 2>&1`

see compare statistics at http://www.imagemagick.org/Usage/compare/#compare