NETPIPES(1)

NAME
netpipes - a package to manipulate BSD TCP/IP stream sockets

SYNOPSIS
faucet port (-in|-out|-err|-fdn) [-once] [-verbose] [-quiet] [-unix] [-foreignhost addr] [-foreignport port] [-localhost addr] [-daemon] [-shutdown (r|w) ] [-serial] [-pidfile filename] [-[i][o][e][#3[,4[,5...]]][v][1][q][u][d][s]] [-p foreign-port] [-h foreign-host] [-H local-host] command args hose hostname port (-in|-out|-err|-fdn|-slave) [-verbose] [-unix] [-localport port] [-localhost addr] [-retry n] [-delay n] [-shutdown [r|w][a] ] [-[i][o][e][#3[,4[,5...]]][s][v][u]] [-p local-port] [-h local-host] command args sockdown [fd [how] ] getpeername [ -verbose ] [ -sock ] [ fd ] getsockname [ -verbose ] [ -peer ] [ fd ]

DESCRIPTION
  The netpipes package makes TCP/IP streams usable in shell scripts. It can also simplify client/server code by allowing the programmer to skip all the tedious programming bits related to sockets and concentrate on writing a filter/service.
  faucet is the server end of a TCP/IP stream. It listens on a port of the local machine waiting for connections. Every time it gets a connection it forks a process to perform a service for the connecting client.
  hose is the client end of a TCP/IP stream. It actively connects to a remote port and execs a process to request a service.
  sockdown is a simple program designed to shut down part or all of the socket connection. It is primarily useful when the processes connected to the socket perform both input and output.
  getpeername and getsockname are two names for a program designed to print out the addresses of the ends of a socket. getpeername prints the address of the remote end and getsockname prints the address of the local end.

EXAMPLES
Here is a simple command I often perform to transfer directory trees between machines. (rsh does not work because one machine is connected using SLIP and .rhosts are out of the question).
    server$ faucet 3000 -out tar cf - .
    client$ hose server 3000 -in tar xvf -
Here is a minimal HTTP client. It is so minimal it speaks old HTTP.
    cairo$ hose www.cis.ufl.edu 80 -in -out \
    	sh -c "(echo 'GET /'; sockdown) & cat > result"
And of course, there is Nick Trown's metaserver for Netrek
    cairo$ hose metaserver.ecst.csuchico.edu 3521 -in cat
Finally, allow me to apologize ahead of time for the convolutedness of the following example. It requires an understanding of Bourne shell file descriptor redirection syntax (and illustrates why csh and tcsh suck eggs). Do not try to type this from your tcsh command line. Get a bash (GNU's Bourne Again SHell).
    server$ faucet 3000 -in -out -verbose enscript -2rGhp -
    client$ ps aux | hose server 3000 -in -out \
    	sh -c " (cat <&3; sockdown ) & cat >&4 " 3<&0 4>&1 | \
    	lpr -Pps422
This proves that hose can be used as part of a pipeline to perform a sort of remote procedure call (RPC). After you have figured out that example, you will know how to use Bourne shell to shuffle file descriptors around. It is a handy skill. Now we go to the extreme, but simplify things by using the -slave option of hose. The following is a socket relay
    gateway$ faucet 3000 -in -out \
    	sh -c "hose server 4000 -slave "
It's a handy little bugger when you want to tunnel through a firewall on an occasional basis.

SEE ALSO
faucet(1), hose(1), sockdown(1), getpeername(1),

COPYRIGHT
Copyright (C) 1995 Robert Forsman 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., 675 Mass Ave, Cambridge, MA 02139, USA.

AUTHOR
 Robert Forsman
 thoth@cis.ufl.edu
 Purple Frog Software
 http://www.purplefrog.com/~thoth/