As the COMPARE command processor proceeds, it will output messages on its progress. If you make a mistake, the messages may give you some idea of what you did wrong. In interpreting any error messages you receive, keep in mind the fact that as each part of the command is interpreted, it is removed from the command line. If you make a typo so something doesn't get deleted, it may be interpreted as something else. For example, if one were to specify,
COMPARE SEGMATCH A B $ - RESMATCH A B RANGES 1 100 10 110 $$
the error messages would say that RANGES is too long to be a residue identifier and that the residue id's are not all paired. The error in the command is that the RANGES command is not terminated by a single delimiter. This results in RANGES being left in, and it and the rest of the command being interpreted as resid pairs. If this seems hopelessly obscure, it unfortunately is.
If one desires a detailed print out of the coordinate matching and atom matching, specify the option, VERBOSE. Your printout will weigh pound instead of ounces.