nsbin/old/replace-old-files

FILE=/tmp/replace-`date +%s`
OLD_STRING=/usr/old-files/bin
NEW_STRING=/usr/bin

if [ $# -ne 1 ]; then
   echo neo
   exit 1
fi

if [ `grep "$OLD_STRING" "$1"` ]; then
   echo "$1"
   cat "$1" | sed "s,$OLD_STRING,$NEW_STRING,g" > "$FILE"
   mv "$FILE" "$1"
fi