#define SWITCH '@'.

there are 4 kinds of commands defined.


SWITCH, SWITCH   This just sends the SWITCH character through. Used to escape
		the switch character.

SWITCH, SWITCH+n Switch to the stream n. Streams are numbered from 1.

SWITCH, SWITCH-1, "%s" , 0
	Do the control sequence "%s" on the local end.
SWITCH, SWITCH-2, "%s" , 0
	Do the control sequence on the remote end.
SWITCH, SWITCH-3, "%s", 0
	Pass the control sequence through to the remote client. This is
	how the results of commands are passed back to the client. A 
	switch, switch-3 sequence is generated in the term server, and passed
	to the client.

"%s" is simply a string of non-zero bytes.  Brackets indicate optional items.
Legal control sequences are.

Option					Returns status?

C_NAME "%s"				No
       "<client name>"
        Sets the name of this client to be '%s'.  Returned by C_STATS
        Does not return success of failure.

C_PUTENV "%s=%s"			No
	 "<variable>=<value>"
        Puts a variable into the environment.  This will be inherited by 
        any C_EXEC commands.

C_CLOSE "[%d]"				No
	"[<client number>]"
	Close the current client's file, or the client number specified file.

C_CLCLOSE "[%d]"			No
          "[<client number>]"
	Close the current client, or the client number specified.

C_DUMB  				No
	Downgrade clients status to dumb. All control message are now
	ignored, and all switch characters become escaped. Only makes
	sense as a local command.

C_DUMP "%d"				No
       "<count>"
	Effectively makes term go dump for the next %d bytes. All command
	bytes are ignored in the data stream until %d bytes have passed.
	Measured from the first byte to be send after the C_DUMP command.
	Sending 0 means to go dumb permanently.


C_CHMOD "%s\n%o [%ld [%ld]]"		No
        "<filename>\n<mode> [<access time> [<modify time>]]"
	Changes the mode of a file, and optionally the access time and 
        modification time.  Times are specified relative to the current
        time.
 
C_SETPEERNAME "%d,%d,%d,%d,%d,%d"	No
              ** cf. RFC 959
	Changes the socket address that will be returned by C_GETPEERNAME.
	This is usefull, if the connection has been redirected.

C_OPEN "%s [%ld [%o]]"			Yes
       "<filename> [<seek value> [<file mode>]]>"
	To attach a O_RDWR|O_CREAT file to the file descriptor.
	(only makes sense as a remote command).

C_UPLOAD "%s [%ld [%o]]"		Yes
       "<filename> [<seek value> [<file mode>]]>"
	To attach a O_TRUNC|O_CREAT|O_TRUNC file to the file descriptor.
	(only makes sense as a remote command).

C_DOWNLOAD "%s [%ld [%o]]"		Yes
       "<filename> [<seek value> [<file mode>]]>"
	To attach a O_RDONLY file to the file descriptor.
	(only makes sense as a remote command).

C_STAT "%s"				"%ld %d %d %ld %ld %o"
       "<filename>"			"<size> <type> <effective permissions>
                                         <access time> <modification time>
					 <file mode>"
        Returns the given stats for the specified file.  <type> is 0 for
        a file, 1 for a directory, and 2 for anything else.  <effective
        permissions> are 4+2+1 for (rwx).  <access time> and <modification
        time> is relative to the current time.

C_UNLINK "%s"				Yes
         "<filename>"
	Unlinks the specified file.

C_EXEC "%s\254%s\%s\254%s\254 ...\254\254" 	Yes
       "<argv 0>\254<argv 1>\254<argv 2>\254...\254\254"
	Forks and exec's the above command.

C_PTYEXEC "%s\254%s...\254\254"		Yes
          "<argv 0>\254<argv 1>\254<argv 2>\254...\254\254"
	Same as C_EXEC, but opens a pty to execute it in first. This is how
	remote shells are spawned.

C_BIND "%u [%d]"			"%u"
       "<port> [<backlog>]"		"<port>"
        Binds the remote port %d.  If <backlog> is greater than 0, will
        listen for <backlog> connections.  Otherwise you will need to use
        C_LISTEN.  <backlog> defaults to 5.   See C_LISTEN.

C_ACCEPT "%d"				"%d,%d,%d,%d,%d,%d"
	 "<client>"			** cf. RFC 959
	Tries to do an accept() on the socket indicated by the client
	number. The number is the result of a C_BIND command.

C_X_SERVER 				Yes
	Tries to connect the display.

C_SOCKET "%s"				Yes
	Tries to open the unix domain socket with name "%s".

C_PORT "[%s:]%d [%d]" 			Yes
       "[<hostname>:]<port> [<old>]"
	Tries to open a connection to <port> on the host specified.
	<hostname> defaults to "remotehost".  If <old> is 0, the socket
        will be closed and recreated, otherwise the existing socket will
        be used.  <old> defaults to 0.

C_LISTEN "%d %d"			No
	"<client> <backlog>"
	Listens to for connections on a bound socket. When a socket is ready
	accept()'ing, a client number is written to the stream. This number
	should be passed as a parameter to C_ACCEPT. It is acceptable to 
	select() on the server socket until it is ready for reading. If it
	is ready for reading, then the socket must be ready for accepting.

C_PRIORITY "%d"				No
           "<priority>"
	Changes the client to the specified value.  Normally priorities range
	from 20 to -20, with 20 allowed the most outgoing term traffic and -20
	allowed the least.  The local priority is separate from the remote
	priority.

C_COMPRESS "%c" 			No
           "<yes or no>"
	Turns on and off compression respectively.  The any of 'y','c','Y','C',
        '1' or '\01' means compress, and 'n', 'u', 'r', 'N', 'U', 'R', '0',
        or '\0' means don't compress.

C_STATS "%d"				Yes --> Varies
	"<option>"
	>= 0 to stat that client number.
	-1 for a space separated list of active client numbers.
	-2 , "%d %d", being the number of bytes fed to the compressor,
		followed by the number of bytes output by the compressor.
	-3 "%d %d", being the number of bytes read from the modem port,
		followed by the number of bytes written to the modem port.
	-4 "%d %d", being the number of packets in the input queue, followed
		by the number of the packets in the output queue.
	-5 "%d" being the baudrate term is operating at.
	-6 being the client number of the client that asked for the C_STATS.

C_SEEK "%d"				Yes
       "<offset>"
	lseek()s to that offset on the file descriptor.

C_RESIZE "%d %d %d"			No
         "<client> <columns> <rows>"
	Sets the window size of <client> to be <columns>
	wide by <rows> high.

C_BINDN "%d"				"%d,%d,%d,%d,%d,%d"
	"<port>"			** cf. RFC 959
	binds a remote port selected by the system. It immediately writes
	back to the stream the remote getsockname() information in the format
	a,b,c,d,e,f (cf. RFC 959). Then it proceeds like C_BIND. 
	(I've added this to support a non-passive termftp client for 
	the benefit of firewalled people. -ot)

C_GETSOCKNAME "[%d]"			"%d,%d,%d,%d,%d,%d"
              "[<client>]"		** cf. RFC 959
	Returns the socket name.

C_GETPEERNAME "[%d]"			"%d,%d,%d,%d,%d,%d"
              "[<%d>]"			** cf. RFC 959
	Returns the peername.

C_GETHOSTNAME "[%s]"			"%lx %s"
              "[<hostname>]"		"<ip address> <proper hostname>"
	Finds the <ip address> and <proper hostname> of the given host.
	If no hostname is specified, it finds the <ip address> and 
	<proper name> of the <hostname> returned with gethostname().

C_BINDS					"%u"
					"<port>"
	Causes term to listen for a single connection from <port> instead
	of the normal unix domain socket.  This only makes sense as a
	local command, when the connecting socket must be tcpip instead
	of unix domain.

C_USOCK "%d %d"				Yes
	"<client> <udp-type>"
	Changes the udp-type of a socket.

C_UBIND "%d %u"				Yes
	"<client> <port>"
	Binds the udp socket of <client> to the specified port.

C_UDPSET "%d:%d,%d,%d,%d,%d,%d"		Yes
         "<client>:<** cf. RFC 959>"
	Sets the default address where the udp socket transmits its data.

C_QUIT "%d"				Yes
       "<option>"
	Shutdown term.  If <option> is 1, it doesn't hangup the modem,
	if 2, it will hangup, if -1 or not specified, performs the default
	shutdown action.

** cf. RFC 959		Is the socket address in the following format:
   "<ip number with ","'s instead of "."'s>,<port/256>,<port%256>"


The very first data packet received may be of the form:

  "VERSION %lu %lx %s"  == "VERSION <term version> <local address> <hostname>"