[TUHS] sockets (was Re: First appearance of named pipes)
Peter Pentchev
roam at ringlet.net
Sat Mar 28 21:12:34 AEST 2020
On Thu, Mar 26, 2020 at 01:38:17PM +1100, Dave Horsfall wrote:
> On Wed, 25 Mar 2020, Grant Taylor via TUHS wrote:
>
> > · netcat's STDOUT to grep's STDIN
> > · grep's STDOUT to netcat's STDIN
>
> Are you trying to set up a loop of processes or something? I'm not sure if
> that is even possible, although you can't rule out creative uses of dup2()
> etc...
This can't really be done with netcat, but it's quite easy to do with
socat; here's an example with a trivial program that reads lines from
its standard input and writes a single line to its standard output:
[roam at straylight ~]$ socat -v tcp4:nimbus.fccf.net:25 exec:./heysmtp.py
> 2020/03/28 13:09:04.005497 length=48 from=0 to=47
220 nimbus.fccf.net ESMTP Postfix (Debian/GNU)\r
< 2020/03/28 13:09:04.018931 length=6 from=0 to=5
QUIT\r
> 2020/03/28 13:09:04.035387 length=15 from=48 to=62
221 2.0.0 Bye\r
[roam at straylight ~]$
All the output was actually from socat because of the "-v" option
specified.
G'luck,
Peter
--
Peter Pentchev roam@{ringlet.net,debian.org,FreeBSD.org} pp at storpool.com
PGP key: http://people.FreeBSD.org/~roam/roam.key.asc
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