diff --git a/pages/common/sum.md b/pages/common/sum.md
index 405d0ba17..f3e509386 100644
--- a/pages/common/sum.md
+++ b/pages/common/sum.md
@@ -1,6 +1,7 @@
 # sum
 
-> Compute checksums and the number of blocks for a file
+> Compute checksums and the number of blocks for a file.
+> A predecessor to the more modern `cksum`.
 
 - Compute a checksum with BSD-compatible algorithm and 1024-byte blocks: