diff --git a/bin/tests/system/nsupdate/tests.sh b/bin/tests/system/nsupdate/tests.sh
index 40714030c4..5902c80324 100755
--- a/bin/tests/system/nsupdate/tests.sh
+++ b/bin/tests/system/nsupdate/tests.sh
@@ -266,7 +266,8 @@ END
 n=`expr $n + 1`
 ret=0
 echo_i "check that unixtime serial number is correctly generated ($n)"
-oldserial=`$DIG $DIGOPTS +short unixtime.nil. soa @10.53.0.1 | awk '{print $3}'` || ret=1
+$DIG $DIGOPTS +short unixtime.nil. soa @10.53.0.1 > dig.out.old.test$n || ret=1
+oldserial=`awk '{print $3}' dig.out.old.test$n` || ret=1
 $NSUPDATE <<END > /dev/null 2>&1 || ret=1
     server 10.53.0.1 ${PORT}
     ttl 600
@@ -275,7 +276,8 @@ $NSUPDATE <<END > /dev/null 2>&1 || ret=1
 END
 now=`$PERL -e 'print time()."\n";'`
 sleep 1
-serial=`$DIG $DIGOPTS +short unixtime.nil. soa @10.53.0.1 | awk '{print $3}'` || ret=1
+$DIG $DIGOPTS +short unixtime.nil. soa @10.53.0.1 > dig.out.new.test$n || ret=1
+serial=`awk '{print $3}' dig.out.new.test$n` || ret=1
 [ "$oldserial" -ne "$serial" ] || ret=1
 # allow up to 2 seconds difference between the serial
 # number and the unix epoch date but no more