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The Lounge What is on Your Mind? Echo eval xargs and other siblings Post 303031580 by nezabudka on Saturday 2nd of March 2019 06:05:57 AM
Old 03-02-2019
Thanks @Corona688,
stdin> this is the shell stdin
I was hoping that it would be clear from the context that the stdin> is the entrance to the shell. I guess I need to work on the design of the presentation. Smilie
It seemed to me funny, for example, "echo" and "eval" commands. Both commands take parameters and do the same work. Only the first returns a string of them to the stdout and the second command to the stdin (shell stdin).
I'v added the feature of Xargs, above noted to my notes.

Last edited by nezabudka; 03-02-2019 at 07:58 AM..
 

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DPIPE(1)						      General Commands Manual							  DPIPE(1)

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>. Virtual Distributed Ethernet December 6, 2006 DPIPE(1)
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