Linux software maker Terra Soft Solutions has hired Kevyn Shortell, former Linux technology manager for Apple Computer. His title, according to Terra Soft, will be "chief trouble maker." His first task: helping finish Yellow Dog Linux 2.0. Shortell brings experience with PowerPC-based computers and a collection of Nerf weapons. Most Linux software runs on machines using Intel-compatible chips, but Loveland, Colo.-based Terra Soft develops Linux software for PowerPC-based computers, the chip architecture in Macs.