diff --git a/examples/fdupes.jac b/examples/fdupes.jac
new file mode 100644
index 00000000..bac4ba07
--- /dev/null
+++ b/examples/fdupes.jac
@@ -0,0 +1,10 @@
+{. invoke like so:
+{. fd . -t f -x md5sum | sort | ja run fdupes.jac
+{. inspired by Yann Le Du: https://twitter.com/Yann_Le_Du/status/1610299070819729410
+
+fn step(acc, this) :=
+  if (substr this 0 32) = (substr (acc->1) 0 32)
+    then (this . Some (this + '\n' + acc->1))
+    else (this . None);
+
+(->2):?step^(''.None) $0