Video Contact Sheet *NIX creates a contact sheet (preview) from videos by taking still captures distributed over the length of the video. The output image contains useful information on the video such as codecs, file size, screen size, frame rate, and length. It requires MPlayer or FFmpeg and ImageMagick. It is confirmed to work on Linux and FreeBSD, and possibly other POSIX/UNIX systems.
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.
IPv6 CARE, "IPv6 Compliant Automatic Runtime Environment", provides an environment where applications instantly become IPv6-compliant ('patch' mode, see RFC6535). It can also generate a diagnosis about the IPv6 compliance of an application ('check' mode). It uses an LD_PRELOAD-based library injection technique.
envbot is an advanced modular IRC bot coded in bash. Features include SSL, IPv6, modularity (with several good modules already), transport modules (including OpenSSL, GnuTLS, netcat, etc.), loading/unloading/reloading of modules at runtime, rehashing configuration at runtime, advanced access control, and much more.
ptee is a Unix shell tool similar to tee, but it allows you to invoke multiple sub-shells in parallel. Standard input to ptee is copied to both normal standard output and to each sub-shell running under ptee. Each sub-command is run concurrently and fed the same input. The output of each sub-command is thrown away, but any shell expression can be used, such as redirecting to a file. Note that there are some limits on ptee. The shell pipeline will only execute at the pace of the slowest sub-command; otherwise large amounts of data would have to be buffered. Also, the shell that ptee invokes requires 'sh'-like semantics, such as supporting the -c option.