diff --git a/doc/ncdu.1 b/doc/ncdu.1
index 464216f..0560dbd 100644
--- a/doc/ncdu.1
+++ b/doc/ncdu.1
@@ -23,6 +23,9 @@ will be decreased to once every 2 seconds in quiet
 mode. Use this feature to save bandwidth over remote
 connections.
 .TP
+\fB-r\fP
+Read-only mode. This will disable the built-in file deletion feature.
+.TP
 \fB-v\fP
 Print version.
 .TP