First off it's all moot, this thread started
from my misreading the code and thinking he
was checking to see if the filename ended in .gz.
Secondly, no I did not suggest using file,
I said do something like file.
Thirdly, while the file will be being read
(and so doing the test may preload it into the
cache), the bytes read will have to be discarded
making that read otherwise worthless. But again, it's all irrelevant.
We now return you to youre regularly scheduled