ChildProt is a child protection policy daemon for Postfix. It checks a list of recipient addresses. If the current recipient address is found, the sender address is verified against a whitelist. If the current sender address is found, the mail will be delivered to the recipient. If the sender address is not found on the whitelist, the mail will be redirected to a delegate of the recipient. If the recipient address is not found the mail will be delivered to the recipient too.
TXR is a new data munging language. TXR's special pattern language provides template-based matching of entire documents or large sections of documents. It also contains a language for functional and imperative programming. It is written in C and takes the form of a utility that is portable to Unix-like platforms and Windows.
cronbot is a wrapper script for cron jobs. Rather than running your job/script directly, you run it through cronbot, and it will allow a little more control to help keep things from getting out of hand. The default behavior is to only allow one instance of your job to run. This can be changed with the --duplicate option. You can also pass in a maximum time of execution for a job or add a random amount time to delay the start of your job. By default, jobs are run with a default "nice" value, which is usually 10.
xc is a simple and handy substitute for sudo. It parses the /etc/xc.conf file, containing a list of identifiers, accesses, and commands. If an identifier (given as an argument to xc) matches the corresponding access (i.e., user or group), the related command is executed. The user can only see the identifiers he can execute, and the real command attached to the identifier remains invisible to him.