diff --git a/development/lyxsocket/.cvsignore b/development/lyxsocket/.cvsignore
new file mode 100644
index 0000000000..82c1e5ff31
--- /dev/null
+++ b/development/lyxsocket/.cvsignore
@@ -0,0 +1 @@
+lyxclient
diff --git a/development/lyxsocket/lyxclient.C b/development/lyxsocket/lyxclient.C
new file mode 100644
index 0000000000..0e7364a7be
--- /dev/null
+++ b/development/lyxsocket/lyxclient.C
@@ -0,0 +1,564 @@
+/**
+ * \file lyxclient.C
+ * This file is part of LyX, the document processor.
+ * Licence details can be found in the file COPYING.
+ *
+ * \author Joćo Luis M. Assirati
+ *
+ * Full author contact details are available in file CREDITS.
+ */
+
+#include <string>
+#include <vector>
+#include <map>
+#include <iostream>
+
+
+// getpid(), getppid()
+#include <sys/types.h>
+#include <unistd.h>
+
+// select()
+#include <sys/select.h>
+
+// opendir(), closedir(), readdir()
+#include <sys/types.h>
+#include <dirent.h>
+
+// stat()
+#include <sys/stat.h>
+
+// socket(), connect()
+#include <sys/socket.h>
+#include <sys/un.h>
+
+// fcntl()
+#include <fcntl.h>
+
+
+using std::string;
+using std::vector;
+using std::cout;
+using std::cerr;
+using std::cin;
+using std::endl;
+
+
+namespace support {
+
+string itoa(unsigned int i)
+{
+	string str;
+	if(!i) {
+		str = "0";
+	} else {
+		while((0 < i) && (i <= 9)) {
+			str = static_cast<char>('0' + i % 10) + str;
+			i /= 10;
+		}
+	}
+	return str;
+}
+
+
+bool prefixIs(string const & a, string const & pre)
+{
+	char const * p_a = a.c_str();
+	char const * p_pre = pre.c_str();
+	while ((*p_a != '\0') && (*p_pre != '\0') && (*p_a == *p_pre)) {
+		++p_a;
+		++p_pre;
+	}
+	if (*p_pre == '\0') return true; 
+	return false;
+}
+
+
+// Parts stolen from lyx::support::DirList()
+// Returns pathnames begining with dir and ending with
+// pathname separator (/ in unix)
+vector<string> lyxSockets(string const & dir, string const & pid)
+{
+	vector<string> dirlist;
+	DIR * dirp = ::opendir(dir.c_str());
+	if (!dirp) {
+		cerr << "lyxclient: Could not read dir " << dir
+		     << ": " << strerror(errno);
+		return dirlist;
+	}
+
+	dirent * dire;
+	while ((dire = ::readdir(dirp))) {
+		string const fil = dire->d_name;
+		if (prefixIs(fil, "lyx_tmpdir" + pid)) {
+			string lyxsocket = dir + '/' + fil + "/lyxsocket";
+			struct stat status;
+			// not checking if it is a socket -- just if it exists
+			if (!::stat(lyxsocket.c_str(), &status)) {
+				dirlist.push_back(lyxsocket);
+			}
+		}
+	}
+
+	::closedir(dirp);
+	return dirlist;
+}
+
+namespace socktools {
+
+int connect(string const & name)
+{
+	int fd; // File descriptor for the socket
+	sockaddr_un addr; // Structure that hold the socket address
+
+	// char sun_path[108]
+	string::size_type len = name.size();
+	if(len > 107) {
+		cerr << "lyxclient: Socket address '" << name
+		     << "' too long." << endl;
+		return -1;
+	}
+	// Synonims for AF_UNIX are AF_LOCAL and AF_FILE
+	addr.sun_family = AF_UNIX;
+	name.copy(addr.sun_path, 107);
+	addr.sun_path[len] = '\0';
+
+	if((fd = ::socket(PF_UNIX, SOCK_STREAM, 0))== -1) {
+		cerr << "lyxclient: Could not create socket: "
+		     << strerror(errno) << endl;
+		return -1;
+	}
+	if(::connect(fd, (struct sockaddr *)&addr, SUN_LEN(&addr)) == -1) {
+		cerr << "lyxclient: Could not connect to socket " << name
+		     << ": " << strerror(errno) << endl;
+		::close(fd);
+		return -1;
+        }
+	if (::fcntl(fd, F_SETFL, O_NONBLOCK) == -1) {
+		cerr << "lyxclient: Could not set O_NONBLOCK for socket: "
+		     << strerror(errno) << endl;
+		::close(fd);
+		return -1;
+	}
+	return fd;
+}
+
+} // namespace socktools
+} // namespace support
+
+
+
+// Class IOWatch ------------------------------------------------------------
+class IOWatch 
+{
+public:
+	IOWatch();
+	void clear();
+	void addfd(int);
+	bool wait(double);
+	bool wait();
+	bool isset(int fd);
+			
+private:
+	fd_set des;
+	fd_set act;
+};
+
+IOWatch::IOWatch() {
+	clear();
+}
+void IOWatch::clear() {
+	FD_ZERO(&des);
+}
+void IOWatch::addfd(int fd) {
+	FD_SET(fd, &des);
+}
+bool IOWatch::wait(double timeout) {
+	timeval to;
+	to.tv_sec = static_cast<long int>(timeout);
+	to.tv_usec = static_cast<long int>((timeout - to.tv_sec)*1E6);
+	act = des;
+	return select(FD_SETSIZE, &act,
+		      (fd_set *)0, (fd_set *)0, &to);
+}
+bool IOWatch::wait() {
+	act = des;
+	return select(FD_SETSIZE, &act,
+		      (fd_set *)0, (fd_set *)0, (timeval *)0);
+}
+bool IOWatch::isset(int fd) {
+	return FD_ISSET(fd, &act);
+}
+// ~Class IOWatch ------------------------------------------------------------
+
+
+// Class LyXDataSocket -------------------------------------------------------
+// Modified LyXDataSocket class for use with the client
+class LyXDataSocket
+{
+public:
+	LyXDataSocket(string const &);
+	~LyXDataSocket();
+	// File descriptor of the connection
+	int fd() const;
+	// Connection status
+	bool connected() const;
+	// Line buffered input from the socket	
+	bool readln(string &);
+	// Write the string + '\n' to the socket
+	void writeln(string const &);
+
+private:
+	// File descriptor for the data socket
+	int fd_;
+	// True if the connection is up
+	bool connected_;
+	// buffer for input data
+	string buffer;
+};
+
+LyXDataSocket::LyXDataSocket(string const & address)
+{
+	if ((fd_ = support::socktools::connect(address)) == -1) {
+		connected_ = false;
+	} else {
+		connected_ = true;
+	}
+}
+
+LyXDataSocket::~LyXDataSocket()
+{
+	::close(fd_);
+}
+
+int LyXDataSocket::fd() const
+{
+	return fd_;
+}
+
+bool LyXDataSocket::connected() const
+{
+	return connected_;
+}
+
+// Returns true if there was a complete line to input
+// A line is of the form <key>:<value>
+//   A line not of this form will not be passed
+// The line read is splitted and stored in 'key' and 'value'
+bool LyXDataSocket::readln(string & line)
+{
+	int const charbuf_size = 100;
+        char charbuf[charbuf_size]; // buffer for the ::read() system call
+	int count;
+	string::size_type pos;
+
+	// read and store characters in buffer
+	while ((count = ::read(fd_, charbuf, charbuf_size - 1)) > 0) {
+		charbuf[count] = '\0'; // turn it into a c string
+		buffer += charbuf;
+	}
+
+	// Error conditions. The buffer must still be
+	// processed for lines read
+	if (count == 0) { // EOF -- connection closed
+		connected_ = false;
+	} else if ((count == -1) && (errno != EAGAIN)) { // IO error
+		cerr << "lyxclient: IO error." << endl;
+		connected_ = false;
+	}
+
+	// Cut a line from buffer
+	if ((pos = buffer.find('\n')) == string::npos)
+		return false; // No complete line stored
+	line = buffer.substr(0, pos);
+	buffer = buffer.substr(pos + 1);
+	return true;
+}
+
+// Write a line of the form <key>:<value> to the socket
+void LyXDataSocket::writeln(string const & line)
+{
+	string linen(line + '\n');
+	int size = linen.size();
+	int written = ::write(fd_, linen.c_str(), size);
+	if (written < size) { // Allways mean end of connection.
+		if ((written == -1) && (errno == EPIPE)) {
+			// The program will also receive a SIGPIPE
+			// that must be catched
+			cerr << "lyxclient: connection closed while writing."
+			     << endl;
+		} else {
+			// Anything else, including errno == EAGAIN, must be
+			// considered IO error. EAGAIN should never happen
+			// when line is small
+			cerr << "lyxclient: IO error: " << strerror(errno);
+		}
+		connected_ = false;
+	}
+}
+// ~Class LyXDataSocket -------------------------------------------------------
+
+
+// Class CmdLineParser -------------------------------------------------------
+class CmdLineParser
+{
+public:
+	typedef int (*optfunc)(vector<char *> const & args);
+	std::map<string, optfunc> helper;
+	std::map<string, bool> isset;
+	bool parse(int, char * []);
+	vector<char *> nonopt;
+};
+
+bool CmdLineParser::parse(int argc, char * argv[])
+{
+	int opt = 1;
+	while(opt < argc) {
+		vector<char *> args;
+		if(helper[argv[opt]]) {
+			isset[argv[opt]] = true;
+			int arg = opt + 1;
+			while((arg < argc) && (!helper[argv[arg]])) {
+				args.push_back(argv[arg]);
+				++arg;
+			}
+			int taken = helper[argv[opt]](args);
+			if(taken == -1) return false;
+			opt += 1 + taken;
+		} else {
+			if(argv[opt][0] == '-') {
+				if((argv[opt][1] == '-')
+				   && (argv[opt][2]== '\0')) {
+					++opt;
+					while(opt < argc) {
+						nonopt.push_back(argv[opt]);
+						++opt;
+					}
+					return true;
+				} else {
+					cerr << "lyxclient: unknown option "
+					     << argv[opt] << endl;
+					return false;
+				}
+			}
+			nonopt.push_back(argv[opt]);
+			++opt;
+		}
+	}
+	return true;
+}
+// ~Class CmdLineParser -------------------------------------------------------
+
+
+
+namespace cmdline
+{
+void usage() 
+{
+	cerr << "Usage: lyxclient [options]" << endl
+	     << "Options are:" << endl
+	     << "  -a address    set address of the lyx socket" << endl
+	     << "  -t directory  set system temporary directory" << endl
+	     << "  -p pid        select a running lyx by pid" << endl
+	     << "  -c command    send a single command and quit" << endl
+	     << "  -g file row   send a command to go to file and row" << endl
+	     << "  -n name       set client name" << endl
+	     << "  -h name       display this help end exit" << endl
+	     << "If -a is not used, lyxclient will use the arguments of -t and -p to look for" << endl
+	     << "a running lyx. If -t is not set, 'directory' defaults to /tmp. If -p is set," << endl
+	     << "lyxclient will connect only to a lyx with the specified pid. Options -c and -g" << endl
+	     << "cannot be set simultaneoulsly. If no -c or -g options are given, lyxclient" << endl
+	     << "will read commands from standard input and disconnect when command read is BYE:"
+	     << endl;
+}
+
+int h(vector<char *> const & arg)
+{
+	usage();
+	exit(0);
+}
+
+string clientName(support::itoa(::getppid()) + ">" + support::itoa(::getpid()));
+int n(vector<char *> const & arg)
+{
+	if(arg.size() < 1) {
+		cerr << "lyxclient: The option -n requires 1 argument."
+		     << endl;
+		return -1;
+	}
+	clientName = arg[0];
+	return 1;
+}
+
+string singleCommand;
+int c(vector<char *> const & arg)
+{
+	if(arg.size() < 1) {
+		cerr << "lyxclient: The option -c requires 1 argument."
+		     << endl;
+		return -1;
+	}
+	singleCommand = arg[0];
+	return 1;
+}
+
+int g(vector<char *> const & arg)
+{
+	if(arg.size() < 2) {
+		cerr << "lyxclient: The option -g requires 2 arguments."
+		     << endl;
+		return -1;
+	}
+	singleCommand = "LYXCMD:server-goto-file-row "
+		+ static_cast<string>(arg[0]) + ' '
+		+ static_cast<string>(arg[1]);
+	return 2;
+}
+
+char * serverAddress;
+int a(vector<char *> const & arg)
+{
+	if(arg.size() < 1) {
+		cerr << "lyxclient: The option -a requires 1 argument."
+		     << endl;
+		return -1;
+	}
+	serverAddress = arg[0];
+	return 1;
+}
+
+string mainTmp("/tmp");
+int t(vector<char *> const & arg)
+{
+	if(arg.size() < 1) {
+		cerr << "lyxclient: The option -t requires 1 argument."
+		     << endl;
+		return -1;
+	}
+	mainTmp = arg[0];
+	return 1;
+}
+
+string serverPid; // Init to empty string
+int p(vector<char *> const & arg)
+{
+	if(arg.size() < 1) {
+		cerr << "lyxclient: The option -p requires 1 argument."
+		     << endl;
+		return -1;
+	}
+	serverPid = arg[0];
+	return 1;
+}
+
+} // namespace cmdline
+
+using support::prefixIs;
+
+int main(int argc, char * argv[])
+{
+	CmdLineParser parser;
+	parser.helper["-h"] = cmdline::h;
+	parser.helper["-c"] = cmdline::c;
+	parser.helper["-g"] = cmdline::g;
+	parser.helper["-n"] = cmdline::n;
+	parser.helper["-a"] = cmdline::a;
+	parser.helper["-t"] = cmdline::t;
+	parser.helper["-p"] = cmdline::p;
+	// Command line failure conditions:
+	if((!parser.parse(argc, argv))
+	   || (parser.isset["-c"] && parser.isset["-g"])
+	   || (parser.isset["-a"] && parser.isset["-p"])) {
+		cmdline::usage();
+		return 1;
+	}
+
+	LyXDataSocket * server;
+
+	if(parser.isset["-a"]) {
+		server = new LyXDataSocket(cmdline::serverAddress);
+		if(!server->connected()) {
+			cerr << "lyxclient: " << "Could not connect to "
+			     << cmdline::serverAddress << endl;
+			return 1;
+		}
+	} else {
+		// We have to look for an address.
+		// serverPid can be empty.
+		vector<string> addrs = support::lyxSockets(cmdline::mainTmp, cmdline::serverPid);
+		vector<string>::iterator addr = addrs.begin();
+		vector<string>::iterator end = addrs.end();
+		while (addr < end) {
+			server = new LyXDataSocket(*addr);
+			if(server->connected()) break;
+			cerr << "lyxclient: " << "Could not connect to "
+			     << *addr << endl;
+			delete server;
+			++addr;
+		}
+		if(addr == end) {
+			cerr << "lyxclient: No suitable server found." << endl;
+			return 1;
+		}
+		cerr << "lyxclient: " << "Connected to " << *addr << endl;
+	}
+	
+	int const serverfd = server->fd();
+	
+	IOWatch iowatch;
+	iowatch.addfd(serverfd);
+
+	// Used to read from server
+	string answer;
+
+	// Send greeting
+	server->writeln("HELLO:" + cmdline::clientName);
+	// wait at most 2 seconds until server responds
+	iowatch.wait(2.0);
+	if(iowatch.isset(serverfd) && server->readln(answer)) {
+		if(prefixIs(answer, "BYE:")) {
+			cerr << "lyxclient: Server disconnected." << endl;
+			cout << answer << endl;
+			return 1;
+		}
+	} else {
+		cerr << "lyxclient: No answer from server." << endl;
+		return 1;
+	}
+
+	if(parser.isset["-g"] || parser.isset["-c"]) {
+		server->writeln(cmdline::singleCommand);
+		iowatch.wait(2.0);
+		if(iowatch.isset(serverfd) && server->readln(answer)) {
+			cout << answer;
+			if(prefixIs(answer, "ERROR:")) return 1;
+			return 0;
+		} else {
+			cerr << "lyxclient: No answer from server." << endl;
+			return 1;
+		}
+	}
+	
+	// Take commands from stdin
+	iowatch.addfd(0); // stdin
+	bool saidbye = false;
+	while((!saidbye) && server->connected()) {
+		iowatch.wait();
+		if(iowatch.isset(0)) {
+			string command;
+			cin >> command;
+			if(command == "BYE:") {
+				server->writeln("BYE:");
+				saidbye = true;
+			} else {
+				server->writeln("LYXCMD:" + command);
+			}
+		}
+		if(iowatch.isset(serverfd)) {
+			while(server->readln(answer))
+				cout << answer << endl;
+		}
+	}
+
+	return 0;
+}
diff --git a/src/ChangeLog b/src/ChangeLog
index 57be76bc3a..f7f6e49167 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2003-10-13  Joao Luis Meloni Assirati <assirati@fma.if.usp.br>
+
+	* lyxsocket.[Ch]: new files. A simple local socket interface for lyx.
+
+	* Makefile.am: add lyxsocket.[Ch].
+
+	* lyx_main.C (error_handler): handle SIGPIPE.
 
 2003-10-13  André Pönitz  <poenitz@gmx.net>
 
diff --git a/src/Makefile.am b/src/Makefile.am
index aba9d4ea53..9a54e1107a 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -209,6 +209,8 @@ lyx_SOURCES = \
 	lyxrow_funcs.h \
 	lyxserver.C \
 	lyxserver.h \
+	lyxsocket.C \
+	lyxsocket.h \
 	lyxtext.h \
 	lyxtextclass.C \
 	lyxtextclass.h \
diff --git a/src/frontends/ChangeLog b/src/frontends/ChangeLog
index 963ae54817..cf56889bf2 100644
--- a/src/frontends/ChangeLog
+++ b/src/frontends/ChangeLog
@@ -1,3 +1,9 @@
+2003-10-13  Joao Luis Meloni Assirati <assirati@fma.if.usp.br>
+
+	* lyx_gui.h (set_datasocket_callback, set_serversocket_callback,
+	remove_datasocket_callback, remove_serversocket_callback):
+	new function declarations, implemented in the various frontends.
+
 2003-10-07  Martin Vermeer  <martin.vermeer@hut.fi>
 
 	* lyx_gui.h: add <string> and other small fixes to make Lars'
diff --git a/src/frontends/gtk/ChangeLog b/src/frontends/gtk/ChangeLog
index 30958b4d12..e7af1db63d 100644
--- a/src/frontends/gtk/ChangeLog
+++ b/src/frontends/gtk/ChangeLog
@@ -1,3 +1,9 @@
+2003-10-13  Angus Leeming  <leeming@lyx.org>
+
+	* lyx_gui.C (set_datasocket_callback, set_serversocket_callback,
+	remove_datasocket_callback, remove_serversocket_callback):
+	placeholder functions, enabling the frontend to be linked.
+
 2003-10-08  Angus Leeming  <leeming@lyx.org>
 
 	Fix doxygen warnings.
diff --git a/src/frontends/gtk/lyx_gui.C b/src/frontends/gtk/lyx_gui.C
index ce655c1fc0..c70778345a 100644
--- a/src/frontends/gtk/lyx_gui.C
+++ b/src/frontends/gtk/lyx_gui.C
@@ -435,6 +435,22 @@ void lyx_gui::remove_read_callback(int fd)
 }
 
 
+void set_datasocket_callback(LyXDataSocket * /* p */)
+{}
+
+
+void remove_datasocket_callback(LyXDataSocket * /* p */)
+{}
+
+
+void set_serversocket_callback(LyXServerSocket * /* p */)
+{}
+
+
+void remove_serversocket_callback(LyXServerSocket * /* p */)
+{}
+
+
 string const lyx_gui::roman_font_name()
 {
 	return "times";
diff --git a/src/frontends/lyx_gui.h b/src/frontends/lyx_gui.h
index f8be6a290d..1ef368778b 100644
--- a/src/frontends/lyx_gui.h
+++ b/src/frontends/lyx_gui.h
@@ -22,6 +22,8 @@ class Dialogs;
 class LColor_color;
 class LyXFont;
 class LyXComm;
+class LyXDataSocket;
+class LyXServerSocket;
 class FuncRequest;
 
 /// GUI interaction
@@ -94,12 +96,16 @@ bool font_available(LyXFont const & font);
  * add a callback for I/O read notification
  */
 void set_read_callback(int fd, LyXComm * comm);
+void set_datasocket_callback(LyXDataSocket *);
+void set_serversocket_callback(LyXServerSocket *);
 
 /**
  * remove a I/O read callback
  * @param fd file descriptor
  */
 void remove_read_callback(int fd);
+void remove_datasocket_callback(LyXDataSocket *);
+void remove_serversocket_callback(LyXServerSocket *);
 
 } // namespace lyx_gui
 
diff --git a/src/frontends/qt2/ChangeLog b/src/frontends/qt2/ChangeLog
index 40bf47a5ae..bc2557df72 100644
--- a/src/frontends/qt2/ChangeLog
+++ b/src/frontends/qt2/ChangeLog
@@ -1,3 +1,9 @@
+2003-10-13  Angus Leeming  <leeming@lyx.org>
+
+	* lyx_gui.C (set_datasocket_callback, set_serversocket_callback,
+	remove_datasocket_callback, remove_serversocket_callback):
+	placeholder functions, enabling the frontend to be linked.
+
 2003-10-13  Lars Gullik Bjųnnes  <larsbj@gullik.net>
 
 	* lyx_gui.C (start): adjust for distpatch change
diff --git a/src/frontends/qt2/lyx_gui.C b/src/frontends/qt2/lyx_gui.C
index 0b1a1fa405..05f02d1ddd 100644
--- a/src/frontends/qt2/lyx_gui.C
+++ b/src/frontends/qt2/lyx_gui.C
@@ -236,6 +236,22 @@ void remove_read_callback(int fd)
 }
 
 
+void set_datasocket_callback(LyXDataSocket * /* p */)
+{}
+
+
+void remove_datasocket_callback(LyXDataSocket * /* p */)
+{}
+
+
+void set_serversocket_callback(LyXServerSocket * /* p */)
+{}
+
+
+void remove_serversocket_callback(LyXServerSocket * /* p */)
+{}
+
+
 string const roman_font_name()
 {
 	if (!use_gui)
diff --git a/src/frontends/xforms/ChangeLog b/src/frontends/xforms/ChangeLog
index 8bca6e674f..d9801ed0d1 100644
--- a/src/frontends/xforms/ChangeLog
+++ b/src/frontends/xforms/ChangeLog
@@ -1,3 +1,9 @@
+2003-10-13  Joao Luis Meloni Assirati <assirati@fma.if.usp.br>
+
+	* lyx_gui.C (set_datasocket_callback, set_serversocket_callback,
+	remove_datasocket_callback, remove_serversocket_callback):
+	functions to inform the core when the socket has changed state.
+
 2003-10-13  Lars Gullik Bjųnnes  <larsbj@gullik.net>
 
 	* lyx_gui.C (start): adjust for dispatch change
diff --git a/src/frontends/xforms/lyx_gui.C b/src/frontends/xforms/lyx_gui.C
index 29e851a86b..bf3bb46e47 100644
--- a/src/frontends/xforms/lyx_gui.C
+++ b/src/frontends/xforms/lyx_gui.C
@@ -29,12 +29,13 @@
 #include "lyxfunc.h"
 #include "lyxrc.h"
 #include "lyxserver.h"
+#include "lyxsocket.h"
 
 #include "graphics/LoaderQueue.h"
 
+#include "support/filetools.h"
 #include "support/lyxlib.h"
 #include "support/os.h"
-#include "support/filetools.h"
 #include "support/path_defines.h"
 
 #include "lyx_forms.h"
@@ -69,6 +70,7 @@ extern BufferList bufferlist;
 
 // FIXME: wrong place !
 LyXServer * lyxserver;
+LyXServerSocket * lyxsocket;
 
 namespace {
 
@@ -289,6 +291,8 @@ void start(string const & batch, vector<string> const & files)
 	// FIXME: some code below needs moving
 
 	lyxserver = new LyXServer(&view.getLyXFunc(), lyxrc.lyxpipes);
+	lyxsocket = new LyXServerSocket(&view.getLyXFunc(),
+			  os::slashify_path(os::getTmpDir() + "/lyxsocket"));
 
 	vector<string>::const_iterator cit = files.begin();
 	vector<string>::const_iterator end = files.end();
@@ -313,6 +317,7 @@ void start(string const & batch, vector<string> const & files)
 	}
 
 	// FIXME: breaks emergencyCleanup
+	delete lyxsocket;
 	delete lyxserver;
 }
 
@@ -382,6 +387,20 @@ void C_read_callback(int, void * data)
 	comm->read_ready();
 }
 
+extern "C"
+void C_datasocket_callback(int, void * data)
+{
+	LyXDataSocket * client = static_cast<LyXDataSocket *>(data);
+	client->server()->dataCallback(client);
+}
+
+extern "C"
+void C_serversocket_callback(int, void * data)
+{
+	LyXServerSocket * server = static_cast<LyXServerSocket *>(data);
+	server->serverCallback();
+}
+
 }
 
 void set_read_callback(int fd, LyXComm * comm)
@@ -389,12 +408,30 @@ void set_read_callback(int fd, LyXComm * comm)
 	fl_add_io_callback(fd, FL_READ, C_read_callback, comm);
 }
 
-
 void remove_read_callback(int fd)
 {
 	fl_remove_io_callback(fd, FL_READ, C_read_callback);
 }
 
+void set_datasocket_callback(LyXDataSocket * p)
+{
+	fl_add_io_callback(p->fd(), FL_READ, C_datasocket_callback, p);
+}
+
+void remove_datasocket_callback(LyXDataSocket * p)
+{
+	fl_remove_io_callback(p->fd(), FL_READ, C_datasocket_callback);
+}
+
+void set_serversocket_callback(LyXServerSocket * p)
+{
+	fl_add_io_callback(p->fd(), FL_READ, C_serversocket_callback, p);
+}
+
+void remove_serversocket_callback(LyXServerSocket * p)
+{
+	fl_remove_io_callback(p->fd(), FL_READ, C_serversocket_callback);
+}
 
 string const roman_font_name()
 {
diff --git a/src/lyx_main.C b/src/lyx_main.C
index f9b845e70e..e813c532e5 100644
--- a/src/lyx_main.C
+++ b/src/lyx_main.C
@@ -214,6 +214,13 @@ static void error_handler(int err_sig)
 	case SIGTERM:
 		// no comments
 		break;
+	case SIGPIPE:
+		// This will be received if lyx tries to write to a socket
+		// whose reading end was closed. It can safely be ignored,
+		// as in this case the ::write() system call will return -1
+		// and errno will be set to EPIPE
+		return;
+		//break;
 	}
 
 	// Deinstall the signal handlers
@@ -222,6 +229,7 @@ static void error_handler(int err_sig)
 	signal(SIGFPE, SIG_DFL);
 	signal(SIGSEGV, SIG_DFL);
 	signal(SIGTERM, SIG_DFL);
+	signal(SIGPIPE, SIG_DFL);
 
 	LyX::emergencyCleanup();
 
@@ -250,6 +258,7 @@ void LyX::init(bool gui)
 	signal(SIGSEGV, error_handler);
 	signal(SIGINT, error_handler);
 	signal(SIGTERM, error_handler);
+	signal(SIGPIPE, error_handler);
 
 	bool const explicit_userdir = setLyxPaths();
 
diff --git a/src/lyxsocket.C b/src/lyxsocket.C
new file mode 100644
index 0000000000..b84a51d15c
--- /dev/null
+++ b/src/lyxsocket.C
@@ -0,0 +1,252 @@
+/**
+ * \file lyxsocket.C
+ * This file is part of LyX, the document processor.
+ * Licence details can be found in the file COPYING.
+ *
+ * \author Lars Gullik Bjųnnes
+ * \author Jean-Marc Lasgouttes
+ * \author Angus Leeming
+ * \author John Levon
+ * \author Joćo Luis M. Assirati
+ *
+ * Full author contact details are available in file CREDITS.
+ */
+
+#include "lyxsocket.h"
+
+#include "debug.h"
+#include "funcrequest.h"
+#include "LyXAction.h"
+#include "lyxfunc.h"
+
+#include "frontends/lyx_gui.h"
+
+#include "support/lyxlib.h"
+#include "support/socktools.h"
+
+#include <iostream>
+
+using std::endl;
+using std::string;
+
+
+// Address is the unix address for the socket.
+// MAX_CLIENTS is the maximum number of clients
+// that can connect at the same time.
+LyXServerSocket::LyXServerSocket(LyXFunc * f, string const & addr)
+	: func(f),
+	  fd_(lyx::support::socktools::listen(addr, MAX_CLIENTS)),
+	  address_(addr)
+{
+	if (fd_ == -1) {
+		lyxerr << "lyx: Disabling LyX socket." << endl;
+		return;
+	}
+	lyx_gui::set_serversocket_callback(this);
+	lyxerr[Debug::LYXSERVER] << "lyx: New server socket "
+				 << fd_ << ' ' << address_ << endl;
+}
+
+
+// Close the socket and remove the address of the filesystem.
+LyXServerSocket::~LyXServerSocket()
+{
+	::close(fd_);
+	lyx::support::unlink(address_);
+	while (!clients.empty()) close(*clients.rbegin());
+	lyxerr[Debug::LYXSERVER] << "lyx: Server socket quitting" << endl;
+}
+
+
+int LyXServerSocket::fd() const
+{
+	return fd_;
+}
+
+
+string const & LyXServerSocket::address() const
+{
+	return address_;
+}
+
+
+// Creates a new LyXDataSocket and checks to see if the connection
+// is OK and if the number of clients does not exceed MAX_CLIENTS
+void LyXServerSocket::serverCallback()
+{
+	LyXDataSocket * client = new LyXDataSocket(this);
+	if (client->connected()) {
+		if (clients.size() == MAX_CLIENTS) {
+			client->writeln("BYE:Too many clients connected");
+		} else {
+			clients.insert(client);
+			lyx_gui::set_datasocket_callback(client);
+			return;
+		}
+	}
+	delete client;
+}
+
+
+// Reads and processes input from client and check
+// if the connection has been closed
+void LyXServerSocket::dataCallback(LyXDataSocket * client)
+{
+	string line;
+	string::size_type pos;
+	bool saidbye = false;
+	while ((!saidbye) && client->readln(line)) {
+		// The protocol must be programmed here
+		// Split the key and the data
+		if ((pos = line.find(':')) == string::npos) {
+			client->writeln("ERROR:" + line + ":malformed message");
+			continue;
+		}
+
+		string const key = line.substr(0, pos);
+		if (key == "LYXCMD") {
+			string const cmd = line.substr(pos + 1);
+			func->dispatch(lyxaction.lookupFunc(cmd));
+			string const rval = func->getMessage();
+			if (func->errorStat()) {
+				client->writeln("ERROR:" + cmd + ':' + rval);
+			} else {
+				client->writeln("INFO:" + cmd + ':' + rval);
+			}
+		} else if (key == "HELLO") {
+			// no use for client name!
+			client->writeln("HELLO:");
+		} else if (key == "BYE") {
+			saidbye = true;
+		} else {
+			client->writeln("ERROR:unknown key " + key);
+		}
+	}
+
+	if (saidbye || (!client->connected())) {
+		close(client);
+	}
+}
+
+
+// Removes client callback and deletes client object
+void LyXServerSocket::close(LyXDataSocket * client)
+{
+	lyx_gui::remove_datasocket_callback(client);
+	clients.erase(client);
+	delete client;
+}
+
+// Debug
+// void LyXServerSocket::dump() const
+// {
+// 	lyxerr << "LyXServerSocket debug dump.\n"
+// 	     << "fd = " << fd_ << ", address = " << address_ << ".\n"
+// 	     << "Clients: " << clients.size() << ".\n";
+// 	if (!clients.empty()) {
+// 		std::set<LyXDataSocket *>::const_iterator client = clients.begin();
+// 		std::set<LyXDataSocket *>::const_iterator end = clients.end();
+// 		for (; client != end; ++client)
+// 			lyxerr << "fd = " << (*client)->fd() << "\n";
+// 	}
+// }
+
+
+LyXDataSocket::LyXDataSocket(LyXServerSocket * serv)
+	:server_(serv),
+	 fd_(lyx::support::socktools::accept(serv->fd()))
+{
+	if (fd_ == -1) {
+		connected_ = false;
+	} else {
+		lyxerr[Debug::LYXSERVER] << "lyx: New data socket " << fd_ << endl;
+		connected_ = true;
+	}
+}
+
+
+LyXDataSocket::~LyXDataSocket()
+{
+	::close(fd_);
+	lyxerr[Debug::LYXSERVER] << "lyx: Data socket " << fd_ << " quitting." << endl;
+}
+
+
+LyXServerSocket * LyXDataSocket::server() const
+{
+	return server_;
+}
+
+
+int LyXDataSocket::fd() const
+{
+	return fd_;
+}
+
+
+bool LyXDataSocket::connected() const
+{
+	return connected_;
+}
+
+
+// Returns true if there was a complete line to input
+bool LyXDataSocket::readln(string & line)
+{
+	int const charbuf_size = 100;
+        char charbuf[charbuf_size]; // buffer for the ::read() system call
+	int count;
+	string::size_type pos;
+
+	// read and store characters in buffer
+	while ((count = ::read(fd_, charbuf, charbuf_size - 1)) > 0) {
+		charbuf[count] = '\0'; // turn it into a c string
+		buffer += charbuf;
+	}
+
+	// Error conditions. The buffer must still be
+	// processed for lines read
+	if (count == 0) { // EOF -- connection closed
+		lyxerr[Debug::LYXSERVER] << "lyx: Data socket " << fd_
+					 << ": connection closed." << endl;
+		connected_ = false;
+	} else if ((count == -1) && (errno != EAGAIN)) { // IO error
+		lyxerr << "lyx: Data socket " << fd_
+		       << ": IO error." << endl;
+		connected_ = false;
+	}
+
+	// Cut a line from buffer
+	if ((pos = buffer.find('\n')) == string::npos) {
+		lyxerr[Debug::LYXSERVER] << "lyx: Data socket " << fd_
+					 << ": line not completed." << endl;
+		return false; // No complete line stored
+	}
+	line = buffer.substr(0, pos);
+	buffer = buffer.substr(pos + 1);
+	return true;
+}
+
+
+// Write a line of the form <key>:<value> to the socket
+void LyXDataSocket::writeln(string const & line)
+{
+	string linen(line + '\n');
+	int size = linen.size();
+	int written = ::write(fd_, linen.c_str(), size);
+	if (written < size) { // Allways mean end of connection.
+		if ((written == -1) && (errno == EPIPE)) {
+			// The program will also receive a SIGPIPE
+			// that must be catched
+			lyxerr << "lyx: Data socket " << fd_
+			       << " connection closed while writing." << endl;
+		} else {
+			// Anything else, including errno == EAGAIN, must be
+			// considered IO error. EAGAIN should never happen
+			// when line is small
+			lyxerr << "lyx: Data socket " << fd_
+			     << " IO error: " << strerror(errno);
+		}
+		connected_ = false;
+	}
+}
diff --git a/src/lyxsocket.h b/src/lyxsocket.h
new file mode 100644
index 0000000000..cadea4cbe7
--- /dev/null
+++ b/src/lyxsocket.h
@@ -0,0 +1,96 @@
+// -*- C++ -*-
+/**
+ * \file lyxsocket.h
+ * This file is part of LyX, the document processor.
+ * Licence details can be found in the file COPYING.
+ *
+ * \author Lars Gullik Bjųnnes
+ * \author Jean-Marc Lasgouttes
+ * \author Joćo Luis M. Assirati
+ *
+ * Full author contact details are available in file CREDITS.
+ */
+
+#ifndef LYXSOCKET_H
+#define LYXSOCKET_H
+
+#include "support/socktools.h"
+#include "lyxfunc.h"
+
+#include <string>
+#include <set>
+
+class LyXServerSocket;
+class LyXDataSocket;
+
+/** Sockets can be in two states: listening and connected.
+ *  Connected sockets are used to transfer data, and will therefore
+ *  be called Data Sockets. Listening sockets are used to create
+ *  Data Sockets when clients connect, and therefore will be called
+ * Server Sockets.
+
+ * This class encapsulates local (unix) server socket operations and
+ * manages LyXDataSockets objects that are created when clients connect.
+ */
+class LyXServerSocket
+{
+public:
+	LyXServerSocket(LyXFunc *, std::string const &);
+	~LyXServerSocket();
+	/// File descriptor of the socket
+	int fd() const;
+	/// Address of the local socket
+	std::string const & address() const;
+	/// To be called when there is activity in the server socket
+	void serverCallback();
+	/// To be called when there is activity in the data socket
+	void dataCallback(LyXDataSocket *);
+
+private:
+	/// Close the connection to the argument client
+	void close(LyXDataSocket *);
+
+	LyXFunc * func;
+	/// File descriptor for the server socket
+	int fd_;
+	/// Stores the socket filename
+	std::string address_;
+	/// Maximum number of simultaneous clients
+	enum {
+                MAX_CLIENTS = 10
+        };
+	/// All connections
+	std::set<LyXDataSocket *> clients;
+};
+
+
+/** This class encapsulates data socket operations.
+ *  It provides read and write IO operations on the socket.
+ */
+class LyXDataSocket
+{
+public:
+	LyXDataSocket(LyXServerSocket *);
+	~LyXDataSocket();
+	/// The object that allocated us
+	LyXServerSocket * server() const;
+	/// File descriptor of the connection
+	int fd() const;
+	/// Connection status
+	bool connected() const;
+	/// Line buffered input from the socket	
+	bool readln(std::string &);
+	/// Write the string + '\n' to the socket
+	void writeln(std::string const &);
+
+private:
+	LyXServerSocket * server_;
+	/// File descriptor for the data socket
+	int fd_;
+	/// True if the connection is up
+	bool connected_;
+	/// buffer for input data
+	std::string buffer;
+};
+
+#endif // LYXSOCKET_H
diff --git a/src/support/Makefile.am b/src/support/Makefile.am
index 235d127016..575e74faf1 100644
--- a/src/support/Makefile.am
+++ b/src/support/Makefile.am
@@ -65,6 +65,8 @@ libsupport_la_SOURCES = \
 	rmdir.C \
 	snprintf.h \
 	snprintf.c \
+	socktools.C \
+	socktools.h \
 	sstream.h \
 	std_istream.h \
 	std_ostream.h \
diff --git a/src/support/socktools.C b/src/support/socktools.C
new file mode 100644
index 0000000000..8e28da55f0
--- /dev/null
+++ b/src/support/socktools.C
@@ -0,0 +1,128 @@
+/**
+ * \file socktools.C
+ * This file is part of LyX, the document processor.
+ * Licence details can be found in the file COPYING.
+ *
+ * \author Joćo Luis M. Assirati
+ *
+ * Full author contact details are available in file CREDITS.
+ */
+
+#include <config.h>
+
+#include "socktools.h"
+#include "debug.h"
+#include "lyxlib.h"
+
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <cerrno>
+
+using std::endl;
+using std::strerror;
+
+using std::string;
+
+
+namespace lyx {
+namespace support {
+namespace socktools {
+
+// Returns a local socket already in the "listen" state (or -1 in case
+// of error). The first argument is the socket address, the second
+// is the length of the queue for connections. If successful, a socket
+// special file 'name' will be created in the filesystem.
+int listen(string const & name, int queue)
+{
+	int fd; // File descriptor for the socket
+	sockaddr_un addr; // Structure that hold the socket address
+
+	// We use 'name' to fill 'addr'
+	string::size_type len = name.size();
+	// the field sun_path in sockaddr_un is a char[108]
+	if (len > 107) {
+		lyxerr << "lyx: Socket address '" << name << "' too long."
+		       << endl;
+		return -1;
+	}
+	// Synonims for AF_UNIX are AF_LOCAL and AF_FILE
+	addr.sun_family = AF_UNIX;
+	name.copy(addr.sun_path, 107);
+	addr.sun_path[len] = '\0';
+
+	// This creates a file descriptor for the socket
+	// Synonims for PF_UNIX are PF_LOCAL and PF_FILE
+	// For local sockets, the protocol is always 0
+	// socket() returns -1 in case of error
+	if ((fd = ::socket(PF_UNIX, SOCK_STREAM, 0))== -1) {
+		lyxerr << "lyx: Could not create socket descriptor: "
+		       << strerror(errno) << endl;
+		return -1;
+	}
+
+	// Set NONBLOCK mode for the file descriptor
+	if (::fcntl(fd, F_SETFL, O_NONBLOCK) == -1) {
+		lyxerr << "lyx: Could not set NONBLOCK mode for socket descriptor: "
+		     << strerror(errno) << endl;
+		::close(fd);
+		return -1;
+	}
+
+	// bind() gives the local address 'name' for 'fd', also creating
+	// the socket special file in the filesystem. bind() returns -1
+	// in case of error
+	if ((::bind (fd, reinterpret_cast<sockaddr *>(&addr), SUN_LEN(&addr))) == -1) {
+		lyxerr << "lyx: Could not bind address '" << name
+		       << "' to socket descriptor: " << strerror(errno) << endl;
+		::close(fd);
+		lyx::support::unlink(name);
+		return -1;
+	}
+
+	// Puts the socket in listen state, that is, ready to accept
+	// connections. The second parameter of listen() defines the
+	// maximum length the queue of pending connections may grow to.
+	// It is not a restriction on the number of connections the socket
+	// can accept. Returns -1 in case of error
+	if (::listen (fd, queue) == -1) {
+		lyxerr << "lyx: Could not put socket in 'listen' state: "
+		       << strerror(errno) << endl;
+		::close(fd);
+		lyx::support::unlink(name);
+		return -1;
+	}
+
+	return fd;
+}
+
+// Returns a file descriptor for a new connection from the socket
+// descriptor 'sd' (or -1 in case of error)
+int accept(int sd)
+{
+	int fd;
+
+	// Returns the new file descriptor or -1 in case of error
+	// Using null pointers for the second and third arguments
+	// dismiss all information about the connecting client
+	if ((fd = accept(sd, reinterpret_cast<sockaddr *>(0), reinterpret_cast<socklen_t *>(0))) == -1) {
+		lyxerr << "lyx: Could not accept connection: "
+		       << strerror(errno) << endl;
+		return -1;
+	}
+
+	// Sets NONBLOCK mode for the file descriptor
+	if (::fcntl(fd, F_SETFL, O_NONBLOCK) == -1) {
+		lyxerr << "lyx: Could not set NONBLOCK mode for connection: "
+		       << strerror(errno) << endl;
+		::close(fd);
+		return -1;
+	}
+	return fd;
+}
+
+} // namespace socktools
+} // namespace support
+} // namespace lyx
diff --git a/src/support/socktools.h b/src/support/socktools.h
new file mode 100644
index 0000000000..22a542c558
--- /dev/null
+++ b/src/support/socktools.h
@@ -0,0 +1,28 @@
+// -*- C++ -*-
+/**
+ * \file socktools.h
+ * This file is part of LyX, the document processor.
+ * Licence details can be found in the file COPYING.
+ *
+ * \author Joćo Luis M. Assirati
+ *
+ * Full author contact details are available in file CREDITS.
+ */
+
+#ifndef SOCKTOOLS_H
+#define SOCKTOOLS_H
+
+#include <string>
+
+namespace lyx {
+namespace support {
+namespace socktools {
+
+int listen(std::string const &, int);
+int accept(int);
+
+} // namespace socktools
+} // namespace support
+} // namespace lyx
+
+#endif // NOT SOCKTOOLS_H