CDParanoia is a package developed by Xiphophorus, the wonderful group of frostily cool folks also responsible for things like Ogg Vorbis.
The package provides a library for CDDA ripping and a command-line tool. The library is being used in variety of programs; If you want a cool GUI front-end, get a Grip. The library itself works in Linux, but the newer incarnation (Paranoia IV) will also work in some other *NIXes (NetBSD, Solaris and others).
cdparanoia started out as an improvement to earlier tool called cdda2wav, but is now a completely separate program.
It's called "paranoia" because it tries to make sure the data was ripped correctly. It's capable of detecting scratches and working around them as best as it can.
Home page: http://www.xiph.org/paranoia/