diff --git a/ChangeLog b/ChangeLog
index e1868314..81e033df 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2008-04-22  Tatsuhiro Tsujikawa  <tujikawa at rednoah dot com>
+
+	Added --quiet option to make aria2 quiet (no console output).
+	--quiet option is tagged with ADVANCED.
+	* src/HelpItemFactory.cc
+	* src/LogFactory.cc
+	* src/LogFactory.h
+	* src/MultiUrlRequestInfo.cc
+	* src/MultiUrlRequestInfo.h
+	* src/NullStatCalc.h: New class. This class prints nothing.
+	* src/OptionHandlerFactory.cc
+	* src/main.cc
+	* src/option_processing.cc
+	* src/prefs.h
+	* src/usage_text.h
+
 2008-04-22  Tatsuhiro Tsujikawa  <tujikawa at rednoah dot com>
 
 	Add HTTP tag to --header option. Removed ADVANCED tag instead.
diff --git a/src/HelpItemFactory.cc b/src/HelpItemFactory.cc
index 89f456be..4c80b189 100644
--- a/src/HelpItemFactory.cc
+++ b/src/HelpItemFactory.cc
@@ -437,6 +437,11 @@ TagContainerHandle HelpItemFactory::createHelpItems()
     item->addTag(TAG_HTTP);
     tc->addItem(item);
   }
+  {
+    HelpItemHandle item(new HelpItem(PREF_QUIET, TEXT_QUIET, V_FALSE));
+    item->addTag(TAG_ADVANCED);
+    tc->addItem(item);
+  }
   {
     HelpItemHandle item(new HelpItem("help", TEXT_HELP, TAG_BASIC));
     char buf[64];
diff --git a/src/LogFactory.cc b/src/LogFactory.cc
index a17c5be3..8ee9df62 100644
--- a/src/LogFactory.cc
+++ b/src/LogFactory.cc
@@ -40,14 +40,17 @@ namespace aria2 {
 
 std::string LogFactory::filename = DEV_NULL;
 Logger* LogFactory::logger = 0;
+bool LogFactory::_consoleOutput = true;
 
 Logger* LogFactory::getInstance() {
   if(logger == NULL) {
     SimpleLogger* slogger = new SimpleLogger();
     slogger->openFile(filename);
-    slogger->setStdout(Logger::NOTICE, true);
-    slogger->setStdout(Logger::WARN, true);
-    slogger->setStdout(Logger::ERROR, true);
+    if(_consoleOutput) {
+      slogger->setStdout(Logger::NOTICE, true);
+      slogger->setStdout(Logger::WARN, true);
+      slogger->setStdout(Logger::ERROR, true);
+    }
     logger = slogger;
   }
   return logger;
diff --git a/src/LogFactory.h b/src/LogFactory.h
index 6ec4197c..804f6958 100644
--- a/src/LogFactory.h
+++ b/src/LogFactory.h
@@ -46,6 +46,7 @@ class LogFactory {
 private:
   static std::string filename;
   static Logger* logger;
+  static bool _consoleOutput;
 public:
   /**
    * Get logger instance. Returned logger is singleton.
@@ -60,6 +61,14 @@ public:
     filename = name;
   }
 
+  /**
+   * Set flag whether the log is printed in console.
+   * If f is false, log is not printed in console.
+   */
+  static void setConsoleOutput(bool f) {
+    _consoleOutput = f;
+  }
+
   /**
    * Releases used resources
    */
diff --git a/src/Makefile.am b/src/Makefile.am
index 5c025d7e..708f4457 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -181,7 +181,8 @@ SRCS =  Socket.h\
 	help_tags.h\
 	prefs.h\
 	usage_text.h\
-	ProtocolDetector.cc ProtocolDetector.h
+	ProtocolDetector.cc ProtocolDetector.h\
+	NullStatCalc.h
 
 if ENABLE_MESSAGE_DIGEST
 SRCS += IteratableChunkChecksumValidator.cc IteratableChunkChecksumValidator.h\
diff --git a/src/Makefile.in b/src/Makefile.in
index 330afe31..1748ebe0 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -404,7 +404,7 @@ am__libaria2c_a_SOURCES_DIST = Socket.h SocketCore.cc SocketCore.h \
 	TrueRequestGroupCriteria.h a2algo.h a2functional.h a2io.h \
 	a2netcompat.h a2time.h array_fun.h help_tags.h prefs.h \
 	usage_text.h ProtocolDetector.cc ProtocolDetector.h \
-	IteratableChunkChecksumValidator.cc \
+	NullStatCalc.h IteratableChunkChecksumValidator.cc \
 	IteratableChunkChecksumValidator.h \
 	IteratableChecksumValidator.cc IteratableChecksumValidator.h \
 	CheckIntegrityCommand.cc CheckIntegrityCommand.h \
@@ -1119,7 +1119,7 @@ SRCS = Socket.h SocketCore.cc SocketCore.h BinaryStream.h Command.cc \
 	TrueRequestGroupCriteria.h a2algo.h a2functional.h a2io.h \
 	a2netcompat.h a2time.h array_fun.h help_tags.h prefs.h \
 	usage_text.h ProtocolDetector.cc ProtocolDetector.h \
-	$(am__append_1) $(am__append_2) $(am__append_3) \
+	NullStatCalc.h $(am__append_1) $(am__append_2) $(am__append_3) \
 	$(am__append_4) $(am__append_5) $(am__append_6) \
 	$(am__append_7) $(am__append_8) $(am__append_9) \
 	$(am__append_10) $(am__append_11) $(am__append_12) \
diff --git a/src/MultiUrlRequestInfo.cc b/src/MultiUrlRequestInfo.cc
index 455004a7..ac394af9 100644
--- a/src/MultiUrlRequestInfo.cc
+++ b/src/MultiUrlRequestInfo.cc
@@ -44,9 +44,10 @@
 #include "message.h"
 #include "DNSCache.h"
 #include "Util.h"
-#include "ConsoleStatCalc.h"
+#include "Option.h"
+#include "StatCalc.h"
 #include <signal.h>
-#include <iostream>
+#include <ostream>
 
 namespace aria2 {
 
@@ -64,9 +65,16 @@ static void handler(int signal) {
   }
 }
 
-MultiUrlRequestInfo::MultiUrlRequestInfo(const RequestGroups& requestGroups, Option* op):
+MultiUrlRequestInfo::MultiUrlRequestInfo
+(const RequestGroups& requestGroups,
+ Option* op,
+ const SharedHandle<StatCalc>& statCalc,
+ std::ostream& summaryOut)
+  :
   _requestGroups(requestGroups),
   _option(op),
+  _statCalc(statCalc),
+  _summaryOut(summaryOut),
   _logger(LogFactory::getInstance())
 {}
 
@@ -74,11 +82,11 @@ MultiUrlRequestInfo::~MultiUrlRequestInfo() {}
 
 void MultiUrlRequestInfo::printMessageForContinue()
 {
-  std::cout << "\n"
-	    << _("aria2 will resume download if the transfer is restarted.")
-	    << "\n"
-	    << _("If there are any errors, then see the log file. See '-l' option in help/man page for details.")
-	    << "\n";
+  _summaryOut << "\n"
+	      << _("aria2 will resume download if the transfer is restarted.")
+	      << "\n"
+	      << _("If there are any errors, then see the log file. See '-l' option in help/man page for details.")
+	      << "\n";
 }
 
 int MultiUrlRequestInfo::execute()
@@ -91,9 +99,8 @@ int MultiUrlRequestInfo::execute()
   try {
     DownloadEngineHandle e =
       DownloadEngineFactory().newDownloadEngine(_option, _requestGroups);
-    SharedHandle<StatCalc> statCalc(new ConsoleStatCalc());
-    e->setStatCalc(statCalc);
 
+    e->setStatCalc(_statCalc);
     e->fillCommand();
 
     // The number of simultaneous download is specified by PREF_MAX_CONCURRENT_DOWNLOADS.
@@ -108,8 +115,8 @@ int MultiUrlRequestInfo::execute()
     
     e->run();
     
-    e->_requestGroupMan->showDownloadResults(std::cout);
-    std::cout << std::flush;
+    e->_requestGroupMan->showDownloadResults(_summaryOut);
+    _summaryOut << std::flush;
 
     RequestGroupMan::DownloadStat s = e->_requestGroupMan->getDownloadStat();
     if(!s.allCompleted()) {
diff --git a/src/MultiUrlRequestInfo.h b/src/MultiUrlRequestInfo.h
index fdc44d20..a66dc9bb 100644
--- a/src/MultiUrlRequestInfo.h
+++ b/src/MultiUrlRequestInfo.h
@@ -38,12 +38,14 @@
 #include "common.h"
 #include "SharedHandle.h"
 #include <deque>
+#include <iosfwd>
 
 namespace aria2 {
 
 class RequestGroup;
 class Option;
 class Logger;
+class StatCalc;
 
 class MultiUrlRequestInfo {
 private:
@@ -51,12 +53,20 @@ private:
 
   Option* _option;
 
+  SharedHandle<StatCalc> _statCalc;
+
+  std::ostream& _summaryOut;
+
   const Logger* _logger;
 
   void printMessageForContinue();
 
 public:
-  MultiUrlRequestInfo(const std::deque<SharedHandle<RequestGroup> >& requestGroups, Option* op);
+  MultiUrlRequestInfo
+  (const std::deque<SharedHandle<RequestGroup> >& requestGroups,
+   Option* op,
+   const SharedHandle<StatCalc>& statCalc,
+   std::ostream& summaryOut);
   
   virtual ~MultiUrlRequestInfo();
 
diff --git a/src/NullStatCalc.h b/src/NullStatCalc.h
new file mode 100644
index 00000000..375fe6bd
--- /dev/null
+++ b/src/NullStatCalc.h
@@ -0,0 +1,54 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2006 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#ifndef _D_NULL_STAT_CALC_H_
+#define _D_NULL_STAT_CALC_H_
+
+#include "StatCalc.h"
+
+namespace aria2 {
+
+class NullStatCalc:public StatCalc {
+public:
+  virtual ~NullStatCalc() {}
+
+  virtual void 
+  calculateStat(const SharedHandle<RequestGroupMan>& requestGroupMan,
+		const SharedHandle<FileAllocationMan>& fileAllocationMan,
+		const SharedHandle<CheckIntegrityMan>& checkIntegrityMan) {}
+};
+
+} // namespace aria2
+
+#endif // _D_NULL_STAT_CALC_H_
diff --git a/src/OptionHandlerFactory.cc b/src/OptionHandlerFactory.cc
index a8e0ce3e..89c34336 100644
--- a/src/OptionHandlerFactory.cc
+++ b/src/OptionHandlerFactory.cc
@@ -127,6 +127,7 @@ OptionHandlers OptionHandlerFactory::createOptionHandlers()
   handlers.push_back(SH(new ParameterOptionHandler(PREF_BT_MIN_CRYPTO_LEVEL, V_PLAIN, V_ARC4)));
   handlers.push_back(SH(new BooleanOptionHandler(PREF_BT_REQUIRE_CRYPTO)));
   handlers.push_back(SH(new CumulativeOptionHandler(PREF_HEADER, "\n")));
+  handlers.push_back(SH(new BooleanOptionHandler(PREF_QUIET)));
   return handlers;
 }
 
diff --git a/src/main.cc b/src/main.cc
index 43ba7585..ad46d475 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -62,6 +62,8 @@
 #include "FileEntry.h"
 #include "RequestGroup.h"
 #include "ProtocolDetector.h"
+#include "ConsoleStatCalc.h"
+#include "NullStatCalc.h"
 #ifdef ENABLE_METALINK
 # include "MetalinkHelper.h"
 # include "Metalink2RequestGroup.h"
@@ -91,6 +93,9 @@ extern int optind, opterr, optopt;
 
 namespace aria2 {
 
+// output stream to /dev/null
+std::ofstream nullout(DEV_NULL);
+
 std::deque<std::string> unfoldURI(const std::deque<std::string>& args)
 {
   std::deque<std::string> nargs;
@@ -119,6 +124,26 @@ RequestGroupHandle createRequestGroup(const Option* op, const std::deque<std::st
   return rg;
 }
 
+SharedHandle<StatCalc> getStatCalc(const Option* op)
+{
+  SharedHandle<StatCalc> statCalc;
+  if(op->getAsBool(PREF_QUIET)) {
+    statCalc.reset(new NullStatCalc());
+  } else {
+    statCalc.reset(new ConsoleStatCalc());
+  }
+  return statCalc;
+}
+
+std::ostream& getSummaryOut(const Option* op)
+{
+  if(op->getAsBool(PREF_QUIET)) {
+    return nullout;
+  } else {
+    return std::cout;
+  }
+}
+
 extern Option* option_processing(int argc, char* const argv[]);
 
 #ifdef ENABLE_BITTORRENT
@@ -157,7 +182,7 @@ int32_t downloadBitTorrent(Option* op, const std::deque<std::string>& uri)
   
   RequestGroups groups;
   groups.push_back(rg);
-  return MultiUrlRequestInfo(groups, op).execute();
+  return MultiUrlRequestInfo(groups, op, getStatCalc(op), getSummaryOut(op)).execute();
 }
 #endif // ENABLE_BITTORRENT
 
@@ -168,7 +193,7 @@ int32_t downloadMetalink(Option* op)
   if(groups.empty()) {
     throw new FatalException("No files to download.");
   }
-  return MultiUrlRequestInfo(groups, op).execute();
+  return MultiUrlRequestInfo(groups, op, getStatCalc(op), getSummaryOut(op)).execute();
 }
 #endif // ENABLE_METALINK
 
@@ -248,7 +273,7 @@ int32_t downloadUriList(Option* op, std::istream& in)
       groups.push_back(rg);
     }
   }
-  return MultiUrlRequestInfo(groups, op).execute();
+  return MultiUrlRequestInfo(groups, op, getStatCalc(op), getSummaryOut(op)).execute();
 }
 
 int32_t downloadUriList(Option* op)
@@ -284,7 +309,7 @@ int32_t downloadUri(Option* op, const std::deque<std::string>& uris)
     RequestGroupHandle rg = createRequestGroup(op, xargs, op->get(PREF_OUT));
     groups.push_back(rg);
   }
-  return MultiUrlRequestInfo(groups, op).execute();
+  return MultiUrlRequestInfo(groups, op, getStatCalc(op), getSummaryOut(op)).execute();
 }
 
 int main(int argc, char* argv[])
@@ -301,6 +326,9 @@ int main(int argc, char* argv[])
   } else {
     LogFactory::setLogFile(DEV_NULL);
   }
+  if(op->getAsBool(PREF_QUIET)) {
+    LogFactory::setConsoleOutput(false);
+  }
   int32_t exitStatus = EXIT_SUCCESS;
   try {
     Logger* logger = LogFactory::getInstance();
diff --git a/src/option_processing.cc b/src/option_processing.cc
index 74cb0044..fb5143b3 100644
--- a/src/option_processing.cc
+++ b/src/option_processing.cc
@@ -143,6 +143,7 @@ Option* option_processing(int argc, char* const argv[])
   op->put(PREF_DHT_FILE_PATH, Util::getHomeDir()+"/.aria2/dht.dat");
   op->put(PREF_BT_MIN_CRYPTO_LEVEL, V_PLAIN);
   op->put(PREF_BT_REQUIRE_CRYPTO, V_FALSE);
+  op->put(PREF_QUIET, V_FALSE);
 
   // following options are not parsed by OptionHandler and not stored in Option.
   bool noConf = false;
@@ -205,6 +206,7 @@ Option* option_processing(int argc, char* const argv[])
       { PREF_CONF_PATH, required_argument, &lopt, 213 },
       { PREF_STOP, required_argument, &lopt, 214 },
       { PREF_HEADER, required_argument, &lopt, 215 },
+      { PREF_QUIET, optional_argument, 0, 'q' },
 #if defined ENABLE_BITTORRENT || ENABLE_METALINK
       { PREF_SHOW_FILES, no_argument, NULL, 'S' },
       { PREF_SELECT_FILE, required_argument, &lopt, 21 },
@@ -243,7 +245,7 @@ Option* option_processing(int argc, char* const argv[])
       { "help", optional_argument, NULL, 'h' },
       { 0, 0, 0, 0 }
     };
-    c = getopt_long(argc, argv, "Dd:o:l:s:pt:m:vh::ST:M:C:a:cU:ni:j:Z::P::", longOpts, &optIndex);
+    c = getopt_long(argc, argv, "Dd:o:l:s:pt:m:vh::ST:M:C:a:cU:ni:j:Z::P::q::", longOpts, &optIndex);
     if(c == -1) {
       break;
     }
@@ -471,6 +473,9 @@ Option* option_processing(int argc, char* const argv[])
     case 'P':
       cmdstream << PREF_PARAMETERIZED_URI << "=" << toBoolArg(optarg) << "\n";
       break;
+    case 'q':
+      cmdstream << PREF_QUIET << "=" << toBoolArg(optarg) << "\n";
+      break;
     case 'v':
       showVersion();
       exit(EXIT_SUCCESS);
diff --git a/src/prefs.h b/src/prefs.h
index 96c5e351..66e034ff 100644
--- a/src/prefs.h
+++ b/src/prefs.h
@@ -126,6 +126,8 @@
 #define PREF_CONF_PATH "conf-path"
 // value: 1*digit
 #define PREF_STOP "stop"
+// value: true | false
+#define PREF_QUIET "quiet"
 
 /**
  * FTP related preferences
diff --git a/src/usage_text.h b/src/usage_text.h
index af3b1d20..dd7f7770 100644
--- a/src/usage_text.h
+++ b/src/usage_text.h
@@ -336,3 +336,5 @@ _(" --header=HEADER              Append HEADER to HTTP request header. You can u
   "                              header:\n"\
   "                              aria2c --header=\"X-A: b78\" --header=\"X-B: 9J1\"\n"\
   "                              http://host/file")
+#define TEXT_QUIET \
+_(" -q, --quiet[=true|false]     Make aria2 quite (no console output).")