command | opie-sh -f to see the output of command in the file viewer. Opie-sh reads in the file until it sees an end of file character, and then displays the text, so its probably best not to display the output from a cat of /dev/ttySA0. You can send an eof by typing Ctr-d on the keyboard. The other option that the file viewer takes is the ``-t'' flag, which sets the title, just like for the other dialogs. If you do not specify the title, it defaults to the name of the file (which is null for stdin). Both of these examples have the same output:
opie-sh -f filename -t "Title" cat filename | opie-sh -f -t "Title"