Replace strings in files using sed

replace.sh

#!/bin/ksh

if [ "$#" -lt 3 ]; then
    echo "Usage: $0 alt_replace ORIGIN DEST FILEMASK" >&2
    exit 1
fi

ORIGIN_STRING=$1
REPLACEMENT_STRING=$2
for ORIG in $(grep -rl $ORIGIN_STRING ${*:3})
do 
    echo "Replacing '$ORIGIN_STRING' by '$REPLACEMENT_STRING' in $ORIG"
    sed -i'' "s/$ORIGIN_STRING/$REPLACEMENT_STRING/g" "$ORIG"
done