diff --git a/devtools/dumper-companion.pl b/devtools/dumper-companion.pl
index 6ac3031ed98..ed72235bcce 100644
--- a/devtools/dumper-companion.pl
+++ b/devtools/dumper-companion.pl
@@ -40,7 +40,7 @@ sub decode_punycode;
 sub encode_punycode;
 sub encode_punycodefilename;
 
-getopts('hmf:c:ed');
+getopts('hmf:c:eds');
 
 if ($::opt_c and $::opt_e) {
 	die "$0: -c and -e are mutually exclusive";
@@ -51,6 +51,14 @@ if ($::opt_h) {
 	exit 0;
 }
 
+if ($::opt_s) {
+	local $/;
+	my $input = <>;
+
+	print encode_punycodefilename($input) . "\n";
+	exit 0;
+}
+
 if ($::opt_m) {
 	processMacbinary;
 	exit 0;
@@ -180,6 +188,10 @@ Mode 2:
 	  Optionally specify encoding (MacRoman, MacJapanese)
 	  If -e is specified, then encode filenames into punycode
 
+Mode 3:
+  $0 -s
+     Read whole standard input and encode it with punycode
+
 Miscellaneous:
   -h, --help   display this help and exit
 EOF