That's because HCOPY outputs a binary file. You can look at the description of the file format here: http://labrosa.ee.columbia.edu/doc/HTKBook21/node58.html#SECTION03271000000000000000

If you want to look at the numerical values of the feature vectors it generates, you could either view the file using a hex editor, or write a script to parse the mfc files and output the vectors. I'm not sure if there's a better way to do it.

Thanks for the reply Kevin!

>if you want to look at the numerical values of the feature vectors it generates

I beleive HList can be used to display the contents of a wav file