strange behaviour from "file -z"

[Robert P. J. Day]

  a nitpicky observation, but "file -z" seems to have problems
with certain compressed files.

  if i "compress" a short text file, i can run "file -z fred.Z",
and it will tell me that it's an ASCII text, compressed data 16
bits file.  so far, so good.

  but if i capture the output of a command with something like

  $ ls -l /usr/bin | compress > lsz

then running "file -z lsz" just sits there.  can anyone explain
this?  is anyone else even seeing this?

rday