NAME

       dpipe - bi-directional pipe command

SYNOPSIS

       dpipe [ command [ args ] ] = [ command [ args ] ]
       dpipe [ command [ args ] ] = [ command [ args ] ] [ = [ command [ args ] ] ] ...

DESCRIPTION

       dpipe  is  a  general  tool to run two commands diverting the standard output of the first
       command into the standard input of the second and vice-versa.  It  is  the  bi-directional
       extension  of  the  |  (pipe)  syntax  used by all the shells.  The = has been chosen as a
       metaphor of two parallel communication lines between the commands.  It is also possible to
       concatenate  several  tools.  Intermediate  programs  communicate using standard input and
       standard  output  with  the  preceding  tool  and  alternate  standard  input  and  output
       (respectively  file  descriptors  number  3  and  4)  towards  the  following tool.  If an
       intermediate tool should process only the data flowing in one direction  use  {  or  }  as
       suffix for the preceding = and prefix of the following one.
       This tool has been written as a tool for the Virtual Distributed Ethernet.

EXAMPLE

       dpipe a = b
       processes  a  and  b are bidirectionally connected: stdin of a is connected to stdout of b
       and vice-versa
       dpipe a = b = c
       a and b are connected as above. Alternate stdin of b is  connected  to  stdout  of  c  and
       alternate stdout of b to stdin of c
       dpipe a =} b }= c
       This  is  a cycle of pipes: stdout of a is connected to stdin of b, stdout of b with stdin
       of c, and stdout of c to stdin of a
       dpipe a =} b }={ c {= d = e
       all the notations can be mixed together.  this is a ->  b  ->  d  ->  c  and  back  to  a;
       alternate ports of d are connected to e

OPTIONS

       no options.

NOTICE

       Virtual  Distributed  Ethernet  is  not  related in any way with www.vde.com ("Verband der
       Elektrotechnik, Elektronik und  Informationstechnik"  i.e.  the  German  "Association  for
       Electrical, Electronic & Information Technologies").

SEE ALSO

       vde_switch(1), vde_plug(1), vde_plug2tap(1), vdeq(1).  wirefilter(1).

AUTHOR

       VDE is a project by Renzo Davoli <renzo@cs.unibo.it>.