How to detect type of compression used on the file? (if no file extension is specified)

Question

How can one detect the type of compression used on the file? (assuming that .zip, .gz, .xz or any other extension is not specified).

Is this information stored somew

Answer 1

If you're on a Linux box just use the 'file' command.

http://en.wikipedia.org/wiki/File_(command)

$ mv foo.zip dink
$ file dink
dink: gzip compressed data, from Unix, last modified: Sat Aug  6 08:08:57 2011,
max compression
$