Batch Rename all mp3's in a directory

I need to rename several hundred mp3's in a directory. I've tried this php script...but it seems to have missed every file from 19 to 29 (119-129, 219-229, 319-329 etc).

The original names are in no particular order or fashion in how they're named.

What's my best choice to rename these files to song1.mp3, song2.mp3 song3.mp3 etc.?

PHP:

<?php
$i = 1;
foreach (glob("/xmas/*.mp3") as $filename) {
copy ("$filename", "/newpopaudio/xmas$i.mp3");
$i++;
}
?>

 

use this ..

i=0
for song in *.mp3
do
mv $song song$i.mp3
((i++))
done

 

go in the directory and run the script.