Shell Programming and Scripting

 if [ $string != $newstring ]; then
((i=i+1))
 echo "$i $newstring" >> $BPATH
awk -F : '($10 == 1)' $BPATH
fi
done < $DPATH

#!/bin/bash

OLD="H"
NEW="M"

DPATH="/home/me/file.dat"
BPATH="/home/me/out.dat"

i=0
while read lineno string data
do
  ((i=i+1))
  echo "$i $string $data" >> $BPATH
  newstring=$( echo $string | tr $OLD $NEW )
  if [ $string != $newstring ]; then
    ((i=i+1))
    new_data=$( echo $data | awk '{$10=1}1' )
    echo "$i $newstring $new_data" >> $BPATH
  fi
done < $DPATH