diff --git a/README.7 b/README.7
index b10929f..c1d9cdb 100644
--- a/README.7
+++ b/README.7
@@ -94,7 +94,7 @@ and Linux.
 On
 .Ox ,
 configure with
-.Fl Fl mandir=/usr/local/man .
+.Fl \-mandir=/usr/local/man .
 .Bd -literal -offset indent
 \&./configure
 make all