userchroot is a small program which, in addition to doing a regular chroot, will also switch working directory once in chroot and drop privileges back to pre-suid values. It is intended to ease constructing chrooted user-driver services (running stfp-server in a restricted namespace for example). In order to conserve system resources, it is implemented in C. This makes it more suitable for higher load scenarios than scripts.
userv is a Unix system facility to allow one program to invoke another when only limited trust exists between them. It is a tool for system administrators, who often find themselves with a program running as one user which needs to be able to do certain things as another user. For example, the author's machine's news system needs to scan its users' newsrcs to ensure that the right newsgroups are fetched. Before userv that part of the news system had to run as root, and clumsily use `su'.
Visprint makes cool fractal fingerprint PNG images based on the contents of any file. The image will be different for almost every file with even slightly different contents. Visprint uses the IFS fractal generation process pioneered by Michael Barnsley. It is a way to create images that are self-similar to infinite depths. In other words, the picture is made up of smaller versions of itself. Visprint takes a hash function checksum as its input.
vlock is a program to lock one or more sessions on the Linux console. This is especially useful for Linux machines which have multiple users with access to the console. One user may lock his or her session(s) while still allowing other users to use the system on other virtual consoles. If desired, the entire console may be locked and virtual console switching disabled.
The vomit utility converts a Cisco IP phone conversation into a wav file that can be played with ordinary sound players. The phone conversation can either be played directly from the network or from a tcpdump output file. Vomit is also capable of inserting wavfiles into ongoing telephone conversations. It can be used as a network debugging tool, a speaker phone, etc.