about audacity and sound recording on Linux

["H.S." <hs.samix@gmail.com>]

Hello,

I just started to use audacity with some live recorded music. I have a 
few starting questions:

Audacity:
1. If the input waveform seems to go beyond the +1 and -1 scale, what 
does that signify? I assume that shows recording circuit is being 
saturated and that the output from mixer should be reduced.
2. If the input waveform is being shown saturated, how would that 
manifest itself in the playback?
3. On a machine, I exported a portion of the captured audio to a wav 
file (basically, saved a portion of the input). I then transfered it to 
my home computer running Debian. While that sound wave file was shown 
between +1 and -1 in the original machine, on my home machine is was 
being shown between +0.5 and -0.5 in audacity. What gives?


Exporting to mp3
1. I would like to export a number of wav files to mp3 files. Instead of 
doing it one by one from audacity, how can I export them using a shell 
script? I want to be able to set some basic tag info in a file and call 
that file to fill in the mp3 tags automatically. In essence, I want to 
call a script that converts all wav files in a directory to mp3 files. 
And of course, I would like to be able to set the bitrate in the script. 
Suggestions on which tool to use for this?
2. I can export to ogg format from audacity. Can I do the same thing as 
(1) for this as well? Does ogg format support tags?

Thanks,
->HS