prepend.sh takes three arguments: directory on which to work, grep regex for files to select, and string to prepend to each file selected by the regex
did some minor configuring of my /etc/bashrc file
fixed line wrapping issue
added a helpful hint at the top
going to try to get SUDO_PS1 to work somehow
did some renaming in case OS X doesn't match up with future Linux stuff; got a nice-looking warning when logged in as root