Compares result using regular expression or mask:
%a% one or more of anything except the end of line characters
%a?% zero or more of anything except the end of line characters
%A% one or more of anything including the end of line characters
%A?% zero or more of anything including the end of line characters
%s% one or more white space characters except the end of line characters
%s?% zero or more white space characters except the end of line characters
%S% one or more of characters except the white space
%S?% zero or more of characters except the white space
%c% a single character of any sort (except the end of line)
%d% one or more digits
%d?% zero or more digits
%i% signed integer value
%f% floating point number
%h% one or more HEX digits