Re: Mental-model of multiprocessing?

From	Unknown <dog@gmail.com>
Newsgroups	comp.os.linux.networking, comp.os.linux.misc
Subject	Re: Mental-model of multiprocessing?
Date	2013-04-03 08:02 +0000
Organization	A noiseless patient Spider
Message-ID	<kjgnmm$rin$1@dont-email.me> (permalink)
References	<rovg2ax8ap.ln2@news.roaima.co.uk> <kj500f$qll$1@dont-email.me> <kjc9b1$nf5$1@dont-email.me>

Cross-posted to 2 groups.

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On Mon, 01 Apr 2013 15:32:49 +0000, Joe Beanfish wrote:

> On Fri, 29 Mar 2013 21:10:40 +0000, Avoid9Pdf wrote:
>> In article <rovg2ax8ap.ln2@news.roaima.co.uk>, Chris Davies
>> <chris-usenet@roaima.co.uk> wrote:
>> But the original code used THIS syntax, and that may be the key to
>> understanding the code. So then:
>>   cat>/tmp/mesgFile
>> (
>>     read line 0<&3 ; echo "$line">$log case "$line" in 2*) ;; *) echo
>>     "QUIT" 1>&3 ; exit 0 ;; esac echo "HELO $local_name" 1>&3
>> ) 3<>/dev/tcp/$smtp_server/25
>> 
>> would mean "stdin [since none is provided]" writeTo /tmp/mesgFile the
>> sequential output of the bracketed-statements [which also write to
>> there OWN destinations]
>> .... ??
> 
> I think part of your confusion is thinking the cat is somehow related to
> the () section.
> 
Yes exactly: with this chaotic/unsequenced syntax, where the redirection
can appear anywhere, I assumed that `cat>/tmp/mesgFile` ALSO hangs on the 
().

> In the above cat will read stdin and write it to mesgFile. The script
> will not proceed until that process is finished, ie when cat's stdin
> reaches end of file. Then the script will proceed to execute the ()
> block with file-descriptor 3 directed to /dev/tcp/$smtp_server/25

What *is* EOF for cat's stdIn? <EnterKey> ?
In the context of the overall task: a SMTP dialog; what is the use of   
`cat>/tmp/mesgFile`  ?

BTW, I've been telling myself and others how good *nix is, because it 
uses the concatenative paradigm: where you can pipe transformations.
And if stage N tests OK, you don't need to worry/remember previous stages.
Now I find that, in this example, if the ()-block is 222-lines, you only
find at the END what FD3 is.  So you've got to carry that info all that 
way. That's crap !!
These FB/twitter kiddies, who've hi-jacked MY thread, need to realise 
that computing progress is not limited by core-count, but by human 
cognitive load. It's fundamental that terms/concepts are defined/
introduced before they are used.
==
Do you see the overall picture of how this code impliments a SMTP-client?
And how the: user, script, logFile, remoteServer; all communicate?

== TIA.

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Thread

Mental-model of multiprocessing? Avoid9Pdf@gmail.com - 2013-03-27 11:13 +0000
  Re: Mental-model of multiprocessing? Joe Beanfish <joebeanfish@nospam.duh> - 2013-03-27 14:02 +0000
    Re: Mental-model of multiprocessing? Richard Kettlewell <rjk@greenend.org.uk> - 2013-03-27 14:13 +0000
      Re: Mental-model of multiprocessing? The Natural Philosopher <tnp@invalid.invalid> - 2013-03-27 14:35 +0000
        Re: Mental-model of multiprocessing? Chris Davies <chris-usenet@roaima.co.uk> - 2013-03-27 15:30 +0000
          Re: Mental-model of multiprocessing? The Natural Philosopher <tnp@invalid.invalid> - 2013-03-27 18:57 +0000
        Re: Mental-model of multiprocessing? Richard Kettlewell <rjk@greenend.org.uk> - 2013-03-27 21:15 +0000
          Re: Mental-model of multiprocessing? The Natural Philosopher <tnp@invalid.invalid> - 2013-03-27 21:36 +0000
          Re: Mental-model of multiprocessing? Aragorn <stryder@telenet.be.invalid> - 2013-03-28 06:56 +0100
      Re: Mental-model of multiprocessing? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2013-03-27 21:47 +0000
    Re: Mental-model of multiprocessing? Avoid9Pdf@gmail.com - 2013-03-29 14:28 +0000
      Re: Mental-model of multiprocessing? The Natural Philosopher <tnp@invalid.invalid> - 2013-03-29 15:32 +0000
        Re: Mental-model of multiprocessing? J G Miller <miller@yoyo.ORG> - 2013-03-29 22:36 +0000
      Re: Mental-model of multiprocessing? Chris Davies <chris-usenet@roaima.co.uk> - 2013-03-29 17:31 +0000
        Re: Mental-model of multiprocessing? Avoid9Pdf@gmail.com - 2013-03-29 21:10 +0000
          Re: Mental-model of multiprocessing? "Chris F.A. Johnson" <cfajohnson@gmail.com> - 2013-03-29 18:55 -0400
            Re: Mental-model of multiprocessing? Unknown <dog@gmail.com> - 2013-03-30 06:01 +0000
          Re: Mental-model of multiprocessing? Chris Davies <chris-usenet@roaima.co.uk> - 2013-03-30 21:28 +0000
          Re: Mental-model of multiprocessing? Joe Beanfish <joebeanfish@nospam.duh> - 2013-04-01 15:32 +0000
            Re: Mental-model of multiprocessing? Unknown <dog@gmail.com> - 2013-04-03 08:00 +0000
              Re: Mental-model of multiprocessing? Joe Beanfish <joebeanfish@nospam.duh> - 2013-04-08 14:47 +0000
            Re: Mental-model of multiprocessing? Unknown <dog@gmail.com> - 2013-04-03 08:02 +0000

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