diff --git a/tests/su/01/run_su.exp b/tests/su/01/run_su.exp
index 2381e03a..05f2e687 100755
--- a/tests/su/01/run_su.exp
+++ b/tests/su/01/run_su.exp
@@ -3,7 +3,7 @@
 set timeout 2
 
 if {$argc != 3} {
-	puts "usage: run_su <user> <password> <prompt>"
+	puts "usage: run_su.exp <user> <password> <prompt>"
 	exit 1
 }