Music is usually stored on audio CDs in an uncompressed format which requires a lot of space (e.g. 700MB for only 80 minutes of audio). CD rippers are designed to extract ("rip") the raw digital audio (in a format commonly called CDDA) from a compact disc to a file or other output.
Extracting the audio from the CD usually involves compressing it so that it requires less space using either lossless compression which provides the same quality at roughly half the size (e.g. APE and FLAC) or lossy compression providing lower quality at roughly a tenth the size (e.g. MP3 and OGG).
From physical discs
See Optical disc drive#Ripping for a list of available software. For example, to extract audio with the package:
$ cdda2wav -vall cddb=0 speed=4 -paranoia paraopts=proof -B -D /dev/sr0
Some CD rippers support burning audio to a CD and transcoding on-the-fly (e.g. cdda2mp3).
To allow cdda2wav to create CUE files, you must also specify
-t all to switch cdda2wav into a mode that creates a single audio data file for the whole CD.
Alternatively, to create a bin and cue file pair from an audio CD, use. For example:
$ cdrdao read-cd --read-raw --datafile cdimage.bin cdimage.cue
The cue file generated by this method is not the same as some may expect from tools like EAC. To convert the cdrdao formatted cue files to a "standard" cue file, try AUR.
From image files
Sometimes rather than a physical disc, only an image is available. The audio tracks can still be extracted from image files.
outputXX.iso and each audio track as
XX is the track number:
$ bchunk -w image.bin image.cue output
For some examples of audio tag editors see List of applications/Multimedia#Audio tag editors.
Converting to other formats
$ lame -V0 input.wav
To convert them to FLAC instead:
$ flac input.wav
Tips and tricks
Testing the ease, or difficulty, of ripping
As a test for the degree of difficulty you would face for a specific extraction process, one might test if they can rip only the audio data of the first track:
cdparanoia --batch --log-debug -- -1
Which will create the
cdparanoia.log log file. And, if successful, a
track01.cdda.wav file. See for other options.
Converting that to MP3 can be accomplished with:
ffmpeg -i track01.cdda.wav -vn -ar 44100 -ac 2 -b:a 192k output-file.mp3
A short description of that ffmpeg line is here.