Gentoo Linux is a versatile and fast Linux distribution for x86, PowerPC, Sparc, and Sparc64 that's geared towards Linux power users. Unlike other distros, it has an advanced package management system called Portage. Portage is a true ports system in the tradition of BSD ports, but is Python-based and sports a number of advanced features including dependencies, fine-grained package management, "fake" (OpenBSD-style) installs, path sandboxing, safe unmerging, system profiles, virtual packages, config file management, and more.
Mandriva is an RPM-based Linux distribtion. It excels at usability and simplicity, features thoroughly preconfigured KDE and GNOME desktops, and includes cool tools like supermount (transparent access to removable media) and DiskDrake (a full-featured graphical hard-drive partitioner). Unlike former versions, Mandriva is not a tuned-up Red Hat, but a very mature Linux distribution on its own. Mandriva is published by a company, but is a completely open and transparent free-software project.
The Project Akita OS (Orange OS) was started with the intent to design a lightweight operating system. It contains a small kernel designed for those interested in the low-level, practical aspects of building an x86 system. The host development environment is designed to work around the Bochs x86 emulator, so that you can easily test changes to the kernel.
The stmpclean utility removes old files (and old empty directories) from the specified directory. It is meant to be used to clean directories such as "/tmp" where old files tend to accumulate. stmpclean never removes files or directories owned by root, which is a feature, not a bug. Great care is taken while descending into the directory, and the operation is secure. Anything that's not a directory, regular file, or symbolic link is also left alone (because programs like screen(1) create sockets and FIFOs under /tmp and expect them to be long-lived). Unlike other programs that do the same task, stmpclean never forks and consumes limited amount of memory. If stmpclean determines a race condition it will log the situation and exit with a failure.