Index: .gitignore
==================================================================
--- .gitignore
+++ .gitignore
@@ -54,5 +54,7 @@
 utils/ofdns/ofdns.exe
 utils/ofhash/ofhash
 utils/ofhash/ofhash.exe
 utils/ofhttp/ofhttp
 utils/ofhttp/ofhttp.exe
+utils/ofsock/ofsock
+utils/ofsock/ofsock.exe

Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -1508,10 +1508,11 @@
 
 	AC_SUBST(OFDNS, "ofdns")
 	AS_IF([test x"$enable_files" != x"no"], [
 		AC_SUBST(OFHTTP, "ofhttp")
 	])
+	AC_SUBST(OFSOCK, "ofsock")
 ])
 
 AC_DEFUN([CHECK_BUILTIN_BSWAP], [
 	AC_MSG_CHECKING(for __builtin_bswap$1)
 	AC_TRY_LINK([

Index: extra.mk.in
==================================================================
--- extra.mk.in
+++ extra.mk.in
@@ -55,10 +55,11 @@
 MAP_LDFLAGS = @MAP_LDFLAGS@
 OFARC = @OFARC@
 OFDNS = @OFDNS@
 OFHASH = @OFHASH@
 OFHTTP = @OFHTTP@
+OFSOCK = @OFSOCK@
 OF_BLOCK_TESTS_M = @OF_BLOCK_TESTS_M@
 OF_EPOLL_KERNEL_EVENT_OBSERVER_M = @OF_EPOLL_KERNEL_EVENT_OBSERVER_M@
 OF_HTTP_CLIENT_TESTS_M = @OF_HTTP_CLIENT_TESTS_M@
 OF_KQUEUE_KERNEL_EVENT_OBSERVER_M = @OF_KQUEUE_KERNEL_EVENT_OBSERVER_M@
 OF_POLL_KERNEL_EVENT_OBSERVER_M = @OF_POLL_KERNEL_EVENT_OBSERVER_M@

Index: utils/Makefile
==================================================================
--- utils/Makefile
+++ utils/Makefile
@@ -2,10 +2,11 @@
 
 SUBDIRS += ${OFARC}	\
 	   ${OFDNS}	\
 	   ${OFHASH}	\
 	   ${OFHTTP}	\
+	   ${OFSOCK}	\
 	   completions
 
 include ../buildsys.mk
 
 DISTCLEAN = objfw-config

ADDED   utils/ofsock/Makefile
Index: utils/ofsock/Makefile
==================================================================
--- utils/ofsock/Makefile
+++ utils/ofsock/Makefile
@@ -0,0 +1,20 @@
+include ../../extra.mk
+
+PROG = ofsock${PROG_SUFFIX}
+SRCS = OFSock.m
+
+include ../../buildsys.mk
+
+PACKAGE_NAME = ofsock
+
+${PROG}: ${LIBOBJFW_DEP_LVL2} ${LIBOBJFWRT_DEP_LVL2}
+
+CPPFLAGS += -I../../src					\
+	    -I../../src/runtime				\
+	    -I../../src/exceptions			\
+	    -I../..
+LIBS := -L../../src -lobjfw						\
+	-L../../src/runtime -L../../src/runtime/linklib ${RUNTIME_LIBS}	\
+	${LIBS}
+LD = ${OBJC}
+LDFLAGS += ${LDFLAGS_RPATH}

ADDED   utils/ofsock/OFSock.m
Index: utils/ofsock/OFSock.m
==================================================================
--- utils/ofsock/OFSock.m
+++ utils/ofsock/OFSock.m
@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017,
+ *               2018, 2019, 2020
+ *   Jonathan Schleifer <js@nil.im>
+ *
+ * All rights reserved.
+ *
+ * This file is part of ObjFW. It may be distributed under the terms of the
+ * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
+ * the packaging of this file.
+ *
+ * Alternatively, it may be distributed under the terms of the GNU General
+ * Public License, either version 2 or 3, which can be found in the file
+ * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
+ * file.
+ */
+
+#include "config.h"
+
+#import "OFApplication.h"
+#import "OFArray.h"
+#import "OFNumber.h"
+#import "OFPair.h"
+#import "OFStdIOStream.h"
+#import "OFStream.h"
+#import "OFString.h"
+#import "OFTCPSocket.h"
+#import "OFURL.h"
+
+#define BUFFER_LEN 4096
+
+@interface OFSock: OFObject <OFApplicationDelegate, OFStreamDelegate>
+{
+	char _buffer[BUFFER_LEN];
+	OFMutableArray OF_GENERIC(OFPair OF_GENERIC(OFStream *, OFStream *) *)
+	    *_streams;
+	int _errors;
+}
+@end
+
+OF_APPLICATION_DELEGATE(OFSock)
+
+static OFPair OF_GENERIC(OFStream *, OFStream *) *
+streamFromString(OFString *string)
+{
+	OFURL *URL;
+	OFString *scheme;
+
+	if ([string isEqual: @"-"])
+		return [OFPair pairWithFirstObject: of_stdin
+				      secondObject: of_stdout];
+
+	URL = [OFURL URLWithString: string];
+	scheme = URL.scheme;
+
+	if ([scheme isEqual: @"tcp"]) {
+		OFTCPSocket *sock = [OFTCPSocket socket];
+
+		if (URL.port == nil) {
+			[of_stderr writeLine: @"Need a port!"];
+			[OFApplication terminateWithStatus: 1];
+		}
+
+		[sock connectToHost: URL.host
+			       port: URL.port.uInt16Value];
+
+		return [OFPair pairWithFirstObject: sock
+				      secondObject: sock];
+	}
+
+	[of_stderr writeFormat: @"Invalid protocol: %@\n", scheme];
+	[OFApplication terminateWithStatus: 1];
+	abort();
+}
+
+@implementation OFSock
+- (void)applicationDidFinishLaunching
+{
+	OFArray OF_GENERIC(OFString *) *arguments = [OFApplication arguments];
+
+	if (arguments.count < 1) {
+		[of_stderr writeLine: @"Need at least one argument!"];
+		[OFApplication terminateWithStatus: 1];
+	}
+
+	_streams = [[OFMutableArray alloc] init];
+
+	for (OFString *argument in arguments) {
+		OFPair *pair = streamFromString(argument);
+
+		[pair.firstObject setDelegate: self];
+
+		[_streams addObject: pair];
+	}
+
+	if (arguments.count == 1) {
+		of_stdin.delegate = self;
+
+		[_streams addObject:
+		    [OFPair pairWithFirstObject: of_stdin
+				   secondObject: of_stdout]];
+	}
+
+	for (OFPair *pair in _streams)
+		[pair.firstObject asyncReadIntoBuffer: _buffer
+					       length: BUFFER_LEN];
+}
+
+- (void)removeDeadStream: (OFStream *)stream
+{
+	size_t count = _streams.count;
+
+	for (size_t i = 0; i < count; i++) {
+		if ([[_streams objectAtIndex: i] firstObject] == stream) {
+			[_streams removeObjectAtIndex: i];
+			break;
+		}
+	}
+
+	if (_streams.count < 2)
+		[OFApplication terminateWithStatus: _errors];
+}
+
+-      (bool)stream: (OFStream *)stream
+  didReadIntoBuffer: (void *)buffer
+	     length: (size_t)length
+	  exception: (id)exception
+{
+	if (exception != nil) {
+		[of_stderr writeFormat: @"Exception on stream %@: %@\n",
+					stream, exception];
+		_errors++;
+		[self removeDeadStream: stream];
+		return false;
+	}
+
+	if (stream.atEndOfStream) {
+		[self removeDeadStream: stream];
+		return false;
+	}
+
+	for (OFPair *pair in _streams) {
+		if (pair.firstObject == stream)
+			continue;
+
+		[pair.secondObject writeBuffer: buffer
+					length: length];
+	}
+
+	return true;
+}
+@end