diff --git a/doc/grep.in.1 b/doc/grep.in.1
index b6362ee..e8334cb 100644
--- a/doc/grep.in.1
+++ b/doc/grep.in.1
@@ -470,6 +470,7 @@ following symbolic links only if they are on the command line.
 This is equivalent to the
 .B "\-d recurse"
 option.
+Note that if no file operand is given, grep searches the working directory.
 .TP
 .BR \-R ", " \-\^\-dereference\-recursive
 Read all files under each directory, recursively.
diff --git a/doc/grep.texi b/doc/grep.texi
index da9a1be..b495cf7 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -699,6 +699,7 @@ read and process all files in that directory, recursively.
 Follow symbolic links on the command line, but skip symlinks
 that are encountered recursively.
 This is the same as the @samp{--directories=recurse} option.
+Note that if no file operand is given, grep searches the working directory.
 
 @item -R
 @itemx --dereference-recursive