Extract audio from a video file in Ubuntu

"mplayer -dumpaudio GummyBearSong.avi -dumpfile gummybear.mp3"

Where:

"GummyBearSong.avi" is the source video, in the example above it was 30 MB
"gummybear.mp3" is the output audio file (in mp3 format), was about 3 MB in size

and surprisingly it took 1 second only!!

I think it runs on other video formats as well, as the source article was working on an "flv" file.

Disable the annoying PC speaker in Ubuntu

Temporarily (doesn't require a restart):

sudo modprobe -r pcspkr

Permanent (requires restart):

sudo your_favorite_text_editor /etc/modprobe.d/blacklist.conf   #text editor can be anything from "vi" to "gedit", whatever you want!

Add this line to the end of the file: "blacklist pcspkr"
Reboot!