#!/bin/bash
for FILE in *.$1
do
FILEFULLNAME=${FILE}
FILE=${FILE##*_} 
FILE=${FILE%%.*}
echo "Creating Dir $FILE"
mkdir "$FILE"
echo "Moving $FILE/$FILEFULLNAME"
mv "$FILEFULLNAME" "$FILE"/"$FILEFULLNAME"
done
# movefilestodirs avi will make dirs and move files of type avi.