This example shows how to rename .mp3 files and add lyrics to them taking all data from near .txt file
eyeD3 --to-v2.4 *.mp3 convert the file's tag to ID3 v2.4
rename 's/[^a-zA-Z0-9_\s.]//g' *.txt renames all .txt files to names without special charachters
Remember!!! The Lyrics text size is 630 chars Itunes can't see lyrics behind this restriction. But iPhone music app can! yeah!