A shell based package manager for embedded *nix systems similar FreeBSD pkgtools.
Apktool is a tool for reverse engineering 3rd party, closed, binary Android apps. It can decode resources to nearly original form and rebuild them after making some modifications. You will find apktool indispensible if you want to extract resources (i.e. images from an Android application. Actually, the tool has no competitors at all!) An online version of the apktool is available here: www.javadecompilers.com/apktool