#! /bin/sh

# Help function
#
function help() {
cat <<-EOF
Usage: `basename $0` [-h] SEDSCRIPT FILE
Runs sed on FILE using SEDSCRIPT as a sed script.

  -h, --help    Display this help text
EOF
}

# The IFS business is to prevent the script from choking on filenames with spaces.
old_ifs=${IFS}
IFS=$'\n'


# Check arguments and issue a help statement, if wrong
#
if [ $# -eq 0 ]; then
  help 
  exit 1
elif [ $1 = "-h" -o $1 = "--help" ]; then
  help 
  exit 0
fi

SEDSCR=$1
shift

for x
do
   echo "editing $x"
   if test "$x" = sedscr; then
      echo "not editing sedscript!" 
   elif test -s $x; then
      y=`basename $x`_$RANDOM
      sed -f $SEDSCR $x > /tmp/$y$$
      echo "Output written to /tmp/$y$$"
      if test -s /tmp/$y$$
      then 
         if cmp -s $x /tmp/$y$$
         then
            echo "file not changed"
         else
            mv $x $x.bak  # save original, just in case
            cp /tmp/$y$$ $x
         fi
         echo "done"
      else 
         echo "Sed produced an empty file"
         echo " - check your sedscript."
      fi
      rm -f /tmp/$y$$
   else
      echo "original file is empty."
   fi
done
echo "all done"

IFS=${old_ifs}