# source: http://www.linuxquestions.org/questions/programming-9/bash-script-to-remove-capitalisation-and-spaces-form-a-filename-309567/

IFS=$'\n'
for f in `find .`; do
   file=$(echo $f | tr [:blank:] '_')
   [ -e $f ] && [ ! -e $file ] && mv "$f" $file
done
unset IFS