[erlang-questions] The Trinity: ERTS, Emulator, Shell

Daniel Dormont <>
Mon Jun 11 16:38:56 CEST 2012


If I may, I think Avinash is asking a slightly more abstract question (or
maybe I'm projecting a similar question I have onto him, could be). Which
is to say, from the standpoint of design, architecture, the relationships
among the different parts of the system, what are the differences among
ERTS, the emulator, and the shell? In other words, when one starts erl
-noshell, what does it mean to not have a shell? What aspects of what I get
when I run plain old "erl" are part of the shell and are therefore missing
if I run erl -noshell?

dan

On Mon, Jun 11, 2012 at 7:49 AM, Prashant Sharma
<>wrote:

> Avinash,
>
> He said so because generally these things are obvious. I like your
> enthusiasm, I will try if I can help!
>
> -detached
> Starts the Erlang runtime system detached from the system console.
> Useful for running daemons and backgrounds processes.
>
> Means it will deamonize the process.
>
> http://www.itp.uzh.ch/~dpotter/howto/daemonize?utm_source=twitterfeed&utm_medium=twitter
> (Full explanation, If you love C)
>
> Which means the process has no terminal(parent) process attached.
> Which in effect would mean that the process does not print anything on
> the console nor can you stop or interact with it.
>
> And when we say no input or no shell. That means the process can not
> receive anything through pipes as in
>
>
> ls | erl
> Eshell V5.10  (abort with ^G)
> 1> * 2: syntax error before: core
> 1> *** Terminating erlang ()
> See its reporting errors as it is trying to interpret input as commands.
>
> ls | erl -noinput
>
> will not show such behavior.
>
> Not sure if you are already aware about unix pipes and input of a
> shell command as argument or via pipe. The above command simply closes
> its pipe.
> http://www.gnu.org/software/libc/manual/html_node/Pipes-and-FIFOs.html
>
> Try this you get the clarity.
>
> To the list: Please correct me If I am wrong.
>
> So before you start reading the books on erlang. You can get some idea
> about these things, I had say try writing an application using MPI and
> stuff just so you understand the pain of doing those things in C.
> Those books start and teach from the perspective of erlang.
>
> From this thread a question sparked in my mind, which is "What would
> one need to know to start learning or working on erlang.?" That would
> mean everything, (Things like understand operating system, processes
> etc). Wish I could list down everything !
>
>
> On Sun, Jun 10, 2012 at 3:23 PM, CGS <> wrote:
> > Then, maybe the next step for you should be to read some books about how
> > Linux manages processes, pipelines and so on so forth.
> >
> > CGS
> >
> >
> >
> >
> >
> >
> >
> >
> > On Sun, Jun 10, 2012 at 7:17 AM, Avinash Dhumane <>
> > wrote:
> >>
> >> Of course, that's where I came from.
> >>
> >> Not that I couldn't employ those options to work fruitfully for the
> >> immediate tasks at hand (towards this end, the online Erlang
> documentation
> >> is adequately equipped) but I am trying to get through them into the
> >> machinery that stands behind them - what that machinery is, how it
> works,
> >> and the most importantly, why it is like what it is. This understanding
> is
> >> indispensable for my self-adaption to Erlang for solving customers'
> >> problems. I guess every programmer-to-be (at various levels) of Erlang
> will
> >> have this need.
> >>
> >> Right now, we have Joe's thesis at one end of the continuum and the
> (open)
> >> source code at the end. The 3 books are very good (and I have them all)
> but
> >> the desire to know, understand and apply is insatiable! :-)
> >>
> >>
> >> On Sun, 10 Jun 2012 03:19:10 +0530, CGS <> wrote:
> >>
> >>> Have you tried http://www.erlang.org/doc/man/erl.html for erl options?
> >>>
> >>> CGS
> >>>
> >>>
> >>>
> >>>
> >>> On Fri, Jun 8, 2012 at 10:24 AM, Avinash Dhumane
> >>> <>wrote:
> >>>
> >>>> Where may I look further for the basic understanding of
> spatio-temporal
> >>>> relations among the "things" named as ERTS, Emulator and Shell? The
> >>>> question occurred while I was toying with "erl" as Unix-filter
> >>>> shell-command and couldn't get over the options (to erl) like
> >>>> "-noshell",
> >>>> "-s", "-detached", init:stop(), and so on in the documentation and in
> >>>> the
> >>>> FAQ.
> >>>>
> >>>> Thanks
> >>>> ______________________________**_________________
> >>>> erlang-questions mailing list
> >>>> 
> >>>>
> >>>> http://erlang.org/mailman/**listinfo/erlang-questions<
> http://erlang.org/mailman/listinfo/erlang-questions>
> >
> >
> >
> > _______________________________________________
> > erlang-questions mailing list
> > 
> > http://erlang.org/mailman/listinfo/erlang-questions
> >
>
>
>
> --
> Prashant Sharma
> Development Engineer
> Pramati Technologies
> Begumpet
>
> "Hare Krishna"
> _______________________________________________
> erlang-questions mailing list
> 
> http://erlang.org/mailman/listinfo/erlang-questions
>
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