BusyBox: The Swiss Army Knife of Embedded Linux

BusyBox combines tiny versions of many common UNIX utilities into a single
small executable. It provides replacements for most of the utilities you
usually find in GNU fileutils, shellutils, etc. The utilities in BusyBox
generally have fewer options than their full-featured GNU cousins; however,
the options that are included provide the expected functionality and behave
very much like their GNU counterparts. BusyBox provides a fairly complete
environment for any small or embedded system.