diff --git a/doc/grep.texi b/doc/grep.texi
index da27aa1..7c80f8c 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -668,7 +668,7 @@ This can cause a performance penalty.
 @cindex memory mapped input
 This option is ignored for backwards compatibility.  It used to read
 input with the @code{mmap} system call, instead of the default @code{read}
-system call.  On modern systems, @samp{--mmap} rarely if ever yields
+system call.  On modern systems, @code{mmap} would rarely if ever yield
 better performance.
 
 @item -U