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

Prashant Sharma <>
Mon Jun 11 13:49:15 CEST 2012


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>
>
>
>
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-- 
Prashant Sharma
Development Engineer
Pramati Technologies
Begumpet

"Hare Krishna"



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