From: Victor Reyes <victor.reyes@...>
Date: 2007-12-28T00:57:17+09:00
Subject: Re: Capturing error msgs from output = `cmd`

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Hi, Stefano,

Well I have partial success at last!

The expression *res =3D `ls abc 2>&1`* works fine on the irb. But not outsi=
de
of it.

For the *Open3* method I tried your suggestion using the *stderr.read* and
it works fine.
I just needed a way to return the outcome of the request to the client
caller.
Since *Open3* works I will stay with it.

Thanks to you, Tim Hunter, James Edward Gray II and Tom Metge for all your
help. It is really appreciated.
One day, when I become good at using Ruby, I might be able to help others.

Victor


On Dec 27, 2007 9:53 AM, Stefano Crocco <stefano.crocco@alice.it> wrote:

> Alle gioved=EC 27 dicembre 2007, Victor Reyes ha scritto:
> > Team,
> >
> > First, thank you for all your suggestions. They are greatly appreciated=
.
> >
> > I tried the:
> > *userCMD_output* *=3D `#{input} 2>&1`*
> > But could not capture the error. Matter of facts the error to the *ls
> > *command was displayed on the screen as:
> > *ls: 0653-341 The file totot does not exist. *
>
> Are you trying it in IRB? in this case, maybe what you see is the return
> value. Try puts userCMD_output and see whether it contains the error
> message
> or not. I tried this and it works:
>
> irb(main):001:0> res =3D `ls abc 2>&1`
> =3D> "ls: impossibile accedere a abc: No such file or directory\n"
> irb(main):002:0> res
> =3D> "ls: impossibile accedere a abc: No such file or directory\n"
>
> > Second, I tried using the *Open3* method and when I tried to display th=
e
> > content of stdin, stdout and stderr just to inspect their contents, thi=
s
> is
> > what's there:
> >
> > *stdin, stdout, stderr =3D Open3.popen3(input)*
> >
> > puts stdin
> > puts stdout
> > puts stderr
> >
> > *#<IO:0x20060638>
> > #<IO:0x200605fc>
> > #<IO:0x20060598> *
>
> I don't understand how this works very well (I just started experimenting
> with
> Open3 yesterday), but I think you need to call their read methods, just a=
s
> you'd do with a file:
>
> puts stdout.read
> =3D> ...
>
> This won't work with stdin (if I remember correctly) because it's not ope=
n
> for
> writing.
>
> I hope this helps
>
> Stefano
>
>

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