#!/bin/bash

unset A1 A2 A3 A4 A5 A6 A7 A8 A9 
unset B1 B2 B3 B4 B5 B6 B7 B8 B9 

read B1 B2 B3 B4 B5 B6 B7 B8 B9 
while [ -n "${B1}" ]; do 
    DIFFS="0"
    unset LASTDIFF
    if [ "${A1}" != "${B1}" ]; then DIFFS=$[ ${DIFFS} + 1 ] ; LASTDIFF="1" ; fi
    if [ "${A2}" != "${B2}" ]; then DIFFS=$[ ${DIFFS} + 1 ] ; LASTDIFF="2" ; fi
    if [ "${A3}" != "${B3}" ]; then DIFFS=$[ ${DIFFS} + 1 ] ; LASTDIFF="3" ; fi
    if [ "${A4}" != "${B4}" ]; then DIFFS=$[ ${DIFFS} + 1 ] ; LASTDIFF="4" ; fi
    if [ "${A5}" != "${B5}" ]; then DIFFS=$[ ${DIFFS} + 1 ] ; LASTDIFF="5" ; fi
    if [ "${A6}" != "${B6}" ]; then DIFFS=$[ ${DIFFS} + 1 ] ; LASTDIFF="6" ; fi
    if [ "${A7}" != "${B7}" ]; then DIFFS=$[ ${DIFFS} + 1 ] ; LASTDIFF="7" ; fi
    if [ "${A8}" != "${B8}" ]; then DIFFS=$[ ${DIFFS} + 1 ] ; LASTDIFF="8" ; fi
    if [ "${A9}" != "${B9}" ]; then DIFFS=$[ ${DIFFS} + 1 ] ; LASTDIFF="9" ; fi

    if [ "${AISREAL}" = "yes" ]; then
	case ${DIFFS} in
	0)
	    #Don't do anything; the lines are identical, so drop one (A)
	    ;;
	1)
	    # Figure out differences here.  Once a replacement for the sole delta field is entered, 
	    # line A can be dropped and B can come around again to be compared to the next line.
	    case ${LASTDIFF} in
	    1)	AVER=${A1} ;     BVER=${B1}       ;;
	    2)	AVER=${A2} ;     BVER=${B2}       ;;
	    3)	AVER=${A3} ;     BVER=${B3}       ;;
	    4)	AVER=${A4} ;     BVER=${B4}       ;;
	    5)	AVER=${A5} ;     BVER=${B5}       ;;
	    6)	AVER=${A6} ;     BVER=${B6}       ;;
	    7)	AVER=${A7} ;     BVER=${B7}       ;;
	    8)	AVER=${A8} ;     BVER=${B8}       ;;
	    9)	AVER=${A9} ;     BVER=${B9}       ;;
	    esac

	    clear
	    echo The following lines differ only in field ${LASTDIFF}.
	    echo ${A1} ${A2} ${A3} ${A4} ${A5} ${A6} ${A7} ${A8} ${A9}
	    echo ${B1} ${B2} ${B3} ${B4} ${B5} ${B6} ${B7} ${B8} ${B9}
	    echo Please enter a suitable replacement for \"${AVER}\" and \"${BVER}\", or
	    echo just press enter to keep \"${BVER}\".
	    unset NEWVER JUNK
	    read NEWVER JUNK
	    if [ -z "${NEWVER}" ]; then
		NEWVER=${BVER}
	    fi

	    case ${LASTDIFF} in
	    1)	B1=${NEWVER}       ;;
	    2)	B2=${NEWVER}       ;;
	    3)	B3=${NEWVER}       ;;
	    4)	B4=${NEWVER}       ;;
	    5)	B5=${NEWVER}       ;;
	    6)	B6=${NEWVER}       ;;
	    7)	B7=${NEWVER}       ;;
	    8)	B8=${NEWVER}       ;;
	    9)	B9=${NEWVER}       ;;
	    esac
	    echo The merged line is:
	    echo ${B1} ${B2} ${B3} ${B4} ${B5} ${B6} ${B7} ${B8} ${B9}
	    ;;
	*)
	    # The lines have more than one field difference.  Just output.
	    echo ${A1} ${A2} ${A3} ${A4} ${A5} ${A6} ${A7} ${A8} ${A9}
	    ;;
	esac
    fi

    A1=${B1} ; A2=${B2} ; A3=${B3} ; A4=${B4} ; A5=${B5} ; A6=${B6} ; A7=${B7} ; A8=${B8} ; A9=${B9}
    AISREAL="yes"
    LASTLINE="${B1} ${B2} ${B3} ${B4} ${B5} ${B6} ${B7} ${B8} ${B9}"

    unset B1 B2 B3 B4 B5 B6 B7 B8 B9 
    read B1 B2 B3 B4 B5 B6 B7 B8 B9 
done
echo ${LASTLINE}