Recs.
Updated
Rubyripper has been the first secure digital audio extraction software (aka. "CD ripper") for GNU/Linux operating systems and it still is the only option with graphical user interface.
Since this application is not present in default repositories of any Linux distribution, you may get lucky and find some third-party repo or you have to rely on manual installation.
After that and possibly setting some configuration work like looking up and entering your drive's read offset value it mostly just works as expected: It produces a set of audion files, in FLAC format or any other you have a command-line encoder for, complete with automatically fetched metadata, generated cue sheet and hidden tracks, all by the press of a button. Biggest downside may be the missing support for verification against other people's ripping results, i.e. integration of AccurateRip or a similar service.
After the retirement of the original author in 2013/2014 some user maintains an active fork on Github.