Xsel is a quick hack to give access to the X selection from the command-line. You can then copy stuff between stdin/stdout and the X selection buffer. For example, 'echo puppa | xsel -c' makes "puppa" the current X selection. 'xsel -p | less' pastes the current X selection to less.
PowerDNS Backend Development Kit allows a developer to code backends which can be loaded at runtime by PowerDNS, a nameserver that reads data from different backends. The stock distribution comes with MySQL and PostgreSQL and other backends. It is also possible to do failover, loadbalancing, and geodirection from a backend.