Reading the man page, I tried to use the pipe mode, by passing the -a option switch. I actually wanted to get back all the words, even the ones that were recognized.
According to the man page, the character ` in the beginning of a line enters the verbose mode, where recognized words are printed after the '*'.
This didn't work, so I took a look at the code. To my surprise, there was nothing there implementing this feature. So I went ahead and wrote the code for it.
I attach the patch file against src/tools/hunspell.cxx