cp: target `track001.mp3' is not a directory
cp: target `track002.mp3' is not a directory
cp: target `track003.mp3' is not a directory
cp: target `track004.mp3' is not a directory
cp: target `track005.mp3' is not a directory
cp: target `track006.mp3' is not a directory
cp: target `track007.mp3' is not a directory
cp: target `track008.mp3' is not a directory
cp: target `track009.mp3' is not a directory

#!/bin/bash
#IFS=$'\n'
echo default IFS:
echo -n "$IFS" | od -a -b
IFS=$'\n'
echo new IFS:
echo -n "$IFS" | od -a -b
for x  in `ls *.mp3`
do
 echo "`sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' $x`"
done
echo new IFS:
echo -n "$IFS" | od -a -b
unset IFS
echo standard IFS:
echo -n "$IFS" | od -a -b

cp "$x" "`sed -ne 's/\([0-9]\{2\}\) - .* - .*[0-9]\{3\}\.mp3/track\1.mp3/gp' $x`"

numbers="$(printf "\n")"; echo -n "$numbers" | od -a -b
0000000

numbers="$(printf "\t")"; echo -n "$numbers" | od -a -b
0000000  ht
        011
0000001