Shell Programming and Scripting

nsupdate_ops() {
        echo "Start NSUPDATE File creation"
        local TEMPFILE=$(mktemp /tmp/nsupdate.XXXXXX)
        exec 7> ${TEMPFILE}
        #echo "server ${DNSSERVER}" >&7
        #echo "zone ${FWDZONE}" >&7
        case ${OPERATION} in
                add_rec|update_rec)
                        printf "server %s\nzone %s\nupdate delete %s A\nupdate add %s 3600 A %s\nsend\n", ${DNSSERVER} ${FWDZONE} ${CN} ${CN} ${ADDRESS} >&7                 
                        ;;
                remove_rec)
                        echo "update delete ${CN}. A" >&7
                        ;;
                add_cname)
                        echo "prereq nxrrset ${CN} A" >&7
                        echo "prereq nxrrset ${CN} CNAME" >&7
                        echo "update add ${CN}. 3600 CNAME ${CNAME}" >&7
                        ;;
                remove_cname)
                        echo "update delete ${CN}. 3600 CNAME ${CNAME}" >&7
                        ;;
        esac
#       echo "send" >&7

        exec 7>&-
        echo "END NSUPDATE File creation"

}

        cat >$TEMPFILE <<EOF
server $DNSSERVER
zone $FWDZONE
update delete ${CN}. A
update add ${CN}. 3600 A $ADDRESS
show
send
EOF

exec 7>&1 # Save a copy of stdout into FD 7
exec 1>"${TEMPFILE}" # Redirect stdout into $TEMPFILE

        echo a
        echo b
        echo c
        echo d

exec 1>&7 # Restore stdout
exec 7>&-