# change_prefix: takes all of the files in the current directory starting in $1
# and modifies their prefix to be $2.
if [ -z "$1" -o -z "$2" ]; then
	echo \
"`basename $0`: requires two parameters--the old prefix to look for in this directory and"
	echo 'the new prefix (without dots) to change the prefix to.'
	\exit
fi
for i in *; do
	if [ "`echo $i | sed -n -e 's/\([^.]*\)\..*$/\1/p'`" = $1 ]; then
		mv $i $2.`strip_prefix $i`
	fi
done