diff --git a/tests/zfs-tests/tests/functional/block_cloning/block_cloning.kshlib b/tests/zfs-tests/tests/functional/block_cloning/block_cloning.kshlib
index 526bd54a2b..50f3a3d262 100644
--- a/tests/zfs-tests/tests/functional/block_cloning/block_cloning.kshlib
+++ b/tests/zfs-tests/tests/functional/block_cloning/block_cloning.kshlib
@@ -53,6 +53,6 @@ function get_same_blocks
 	    awk '/ L0 / { print l++ " " $3 " " $7 }' > $zdbout.a
 	zdb $KEY -vvvvv $3 -O $4 | \
 	    awk '/ L0 / { print l++ " " $3 " " $7 }' > $zdbout.b
-	echo $(sort $zdbout.a $zdbout.b | uniq -d | cut -f1 -d' ')
+	echo $(sort -n $zdbout.a $zdbout.b | uniq -d | cut -f1 -d' ')
 }