BusyBox combines tiny versions of many common UNIX utilities into a single small executable. It provides minimalist 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 POSIX environment for any small or embedded system.
daemon turns other processes into daemons. There are many tedious tasks that need to be performed to correctly set up a daemon process; daemon performs these tasks for other processes. This is useful for writing daemons in languages other than C, C++, or Perl (e.g. sh, Java). If you want to write daemons in languages that can link against C functions (e.g. C, C++), see libslack, which contains the core functionality of daemon.
Firewall is a set of scripts (firewall, fwup, and fwdown) that implement an ipchains firewall and various forms of network address and port translation. All you have to do is read the policy file and edit it to reflect your topology and filtering policy. It supports many different types of network topology (single host, traditional forwarding, masquerading, port forwarding, alias port forwarding and NAT), up to 10 untrusted interfaces each with their own policy, and over 50 network applications. It also supports centralised administration of multiple remote firewalls (meta-firewall).
gBootRoot makes the construction and development of distributions fun and simple with its Root Methods (Yard) and user-mode-linux test bed. Finish the product with a Boot Method (2-disk compression supported). Normal (non-root) users can make root filesystems and boot disks. It includes the make_debian script to create a testable user-mode-linux base Debian system, add-ons to enhance methods, and an MTD Emulator useful for running distributions made with the jffs/jffs2 filesystem.
The JACAL Project is a suite of programs, scripts, guidelines, protocols, documentation, and diskettes that assist in quick, network based loads/builds of machines. It has been used to build 70 University lab machines from scratch (No OS) in two hours. This includes NT service packs and 80+ applications on the NT side.
minit is an attempt to cross-breed DJ Bernstein's daemontools and init, while adding dependencies, and maintaining minimal code base. It is possible to start and stop services on the fly. minit does not depend on a mounted /proc file system, and it does not write to any part of the file system, not even to start and stop services. It does not use System V IPC, either.