Whipper is a free secure digital audio extraction software (aka "CD ripper") for GNU/Linux operating systems based on the discontinued morituri.
Users of Debian-based systems like Ubuntu or Linux Mint may install from Christian Marillat's third-party software repository that is available at deb-multimedia.org.
SpecsUpdate
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Pros
Pro Actively developped
It might be the only secure ripper for GNU/Linux that's in active development besides Rubyripper as of 2019.
Pro Most features
(of any secure ripper on Linux so far (2019))
Cons
Con Might refuse service if it can't access impeccable metadata for your disc
Must use --unknown flag if ripping a CD which doesn't have a matching TOC in the MusicBrainz database.
Con No graphical user interface
As of 2019 there is no GUI available yet, so some users may be repelled or have a steep learning curve. If you can't do without a GUI you may want to give the somewhat more limited Rubyripper a try.