In order for the script to work you will need to download ffmpeg (to decode the video) and lame (to encode the mp3). This can be achieve in ubuntu by opening a terminal and running the following or alternatively you can use your package manager GUI to search and download the packages for you.

sudo apt-get install ffmpeg lame

You then need to create a new file named “flv2mp3.sh” and paste the following into it using your preferred text editor (which hopefully isn’t VI). Save the file and then change the file permissions so that it is executable (by running:`chmod a+x flv2mp3.sh` in the terminal or via the gui in you file browser)

#!/bin/sh
# this script should convert files from FLV to WAV and then to MP3
echo " "
echo "  Welcome to FLV to MP3 converter!  version 0.1"
echo " "
infile_name="$@"
# exit if the user did not enter anything:
if [ -z "$infile_name" ]; then
    echo " "
    echo "You did not tell me the file name, so I will exit now."
    echo " "
    exit
fi
echo " "
ffmpeg -i "$infile_name" -acodec pcm_s16le -ac 2 -ab 128k -vn -y "${infile_name%.flv}.wav"
lame --preset cd "${infile_name%.flv}.wav" "${infile_name%.flv}.mp3"
rm "${infile_name%.flv}.wav"
echo " "
echo "OK. I'm done! Have fun!"
echo " "
exit

You should now be able to convert a flashvideo into an mp3 by running the following command (changing the filenames to fit your purpose):
sh flv2mp3.sh videofilename.flv mp3audiofilename.mp3

Extra: Youtube
In linux it might be worth noting that youtube downloads the flv’s to your /tmp folder and you can easily copy them or convert to mp3′s (Ensure video is completly finished loading).

Also there is an application called ‘youtube-dl’ which can be installed from the repositories

sudo apt-get install youtube-dl

and then run using

youtube-dl http://www.youtube.com/video_to_borrow

Of course it’s up to your moral guidance to decide what you can and can’t download.

Chrome: It is sexy (only thing holding it back in Linux is the lack of flash support)
Score: 100/100
Version: 4.0.203.2

Opera: I used to use opera however not really any more, just installed it for this test.
Score: 100/100
Version: 10.00 (build 4585)

Arora: I don’t tend to use Arora, however I’ve heard alot of good things about it. It is a light-weight browser based on web-kit (as are chrome, safari and konqueror) and excels at its speed, highly recommended for notebooks which don’t need the bloat of firefox.
Score: 100/100 Linktest failed.
Version:0.8.0

Firefox: It seems to handle flash better (without crashing) and has lots of useful plugins.
Score: 93/100
Version: 3.5.2

Konqueror:
Score: 89/100 Linktest failed.
Version: 4.3.1

Google’s chrome comes first (with chrome having smoother and faster animation) followed by Opera and closely followed by Arora only failing on the link test, then firefox and trailing is konqueror. But I still love konqueror as its so convenient have filemanager and web-browser in one.