spi (Salix Package Installer) is a command line tool that acts as a
wrapper around slapt-get and slapt-src.

It searches both package (slapt-get) and SlackBuild (slapt-get) local
caches for software. It can also update both local caches.

When installing software, if a package is available through slapt-get,
it will install it, otherwise it will install it through slapt-src. If
any SlackBuild dependencies are available through slapt-get, it will
install them through slapt-get.