unalias ls

for i in `ls`
do

NAME=`echo $i | cut -f1 -d.`
EXT=`echo  $i | cut -f2 -d.`

NEWNAME=`echo ${NAME} | tr "[:upper:]" "[:lower:]" `
NEWEXT=`echo ${EXT} | tr "[:upper:]" "[:lower:]" `

if [ $NAME != $EXT ]
  then
    echo ${NAME}.${EXT} -\> ${NEWNAME}.${NEWEXT}
    mv ${i} ${NEWNAME}.${NEWEXT}
  else echo ${NAME} -\> ${NEWNAME}
    mv ${i} ${NEWNAME}
fi
done