apt-cache performs a variety of operations on APT's package cache. apt-cache does not manipulate the state of the system but does provide operations to search and generate interesting output from the package meta data.
showpkg displays information about the packages listed on the command line
Continue Reading... showpkg displays information about the packages listed on the command line
apt-cache showpkg firefoxStats displays some statistics about the cache
apt-cache statsDump shows a short listing of every package in the cache. It is primarily for debugging.
apt-cache dump firefox
source:http://linuxpoison.blogspot.com/2012/03/13578167756524.html