gistfile1.sh

get_field_index () {
  FILENAME=$1
  FIELD=$2

  IFS=$'\t' read -a KEYS < $FILENAME

  for i in `seq 0 $(( ${#KEYS[*]} - 1))` ; do
    if [ "${KEYS[$i]}" = "$FIELD" ] ; then
      echo $(( $i + 1 ))
      return 0
    fi
  done

  return 1 # not found
}

if LASAGNA=`get_field_index example.txt "Lasagna"` ; then
  echo "Lasagna is \$$LASAGNA"
else
  echo "Error!" 1>&2
fi