x10ephem computes sunrise and sunset times. It consists of a library and an assortment of utilities. The most useful utility is x10events, which parses crontab files and updates the time fields to track sun events. Combined with an X10 interface like HEYU or X10, this allows the scheduling of lighting events to follow the changing seasons and daylight savings time automatically. This application does not depend on X10; it can be used for any crontab entry you like.
x509watch is a simple command line application that can be used to list soon expiring or already expired X.509 certificates, such as SSL certificates. All certificates are searched by default in the standard PKI directory, but any other directory can be specified as a parameter. Only Base64 encoded DER and PEM X.509 certificates are supported.
XAD is a Linux-PAM module which allows a system administrator to control authentication in a very fine-grained manner. This module is very easy to configure, and allows access to be controlled on the basis of many properties of the system or the user who is trying to authenticate.
xlax is an X11 input multiplexer: it sends your keyboard input from the xlax window to a group of windows simultaneously. The tool is designed for system administrators who typically have to do the same thing on several machines (or in several different directories). Windows can be added or deleted interactively, or temporarily disconnected and reconnected. xlax allows you to assign a custom string to each window (e.g. a hostname) that can be sent with a button click. An included script handles starting up and arranging windows, and allows you to set up commonly used window groupings in a config file.
xml2hostconf generates RPM packages, dhcpd.conf, pxelinux files, kickstart files, and HTML documentation with XSLT. It is a framework for central configuration and automatic installation of a Fedora/Redhat Linux network. Configuration files get shipped to the client computers by generated RPMs.