vnStat is a console-based network traffic monitor that keeps a log of hourly, daily, and monthly network traffic for the selected interface(s). It uses the network interface statistics provided by the kernel as information source. This means that vnStat won't actually be sniffing any traffic, and also ensures light use of system resources.
vtwatch automatically switches the active virtual console on your Linux system in a loop, acting as a virtual terminal surveillance monitor. The speed at which they switch is configurable, and it is possible to input a search string, which you are notified about if it is found on a console.
waitcond is a script to specify a combination of events using boolean expressions over various events. It can periodically grep in files, wait for the (dis)appearance of files or processes, wait for certain CPU/net/disk idle values, or wait for an idle tty. waitcond is meant to be combined with some notification tool or system.
Wapsh allows users to login to a Unix workstation using a WAP-capable mobile phone. Features include shortcuts (to save phone typing), input of control and other special characters, command history, and searching and scrolling through long shell output. Wapsh automatically adapts to the main WAP browsers (UP and Nokia), and uses configuration files to further tailor the system for specific phones. A corresponding HTML (Web) interface is also included.
wavemon is a ncurses-based monitor for wireless devices. It allows you to watch the signal and noise levels, packet statistics, device configuration, and network parameters of your wireless network hardware. It has currently only been tested with the Lucent Orinoco series of cards, although it should work (with varying features) with all devices supported by the wireless kernel extensions written by Jean Tourrilhes.