First of all, install Slackware (:D)
Thanks linuxbasics.org for the guidance
You will need oggdec and lame. Download it from slackbuilds.org
1. Oggdec is simple decoder, Ogg Vorbis file to PCM audio file ( Wav or Raw )
2. Lame, create mp3 audio files
Syntax:
$ oggdec audiofile.ogg
that will create audiofile.wav
$ lame audiofile.wav audiofile.mp3
that will create audiofile.mp3
done