Asp Forum - Piping problem

Pawel Radecki

11/24/2007 4:53:00 PM

Hello everybody!

I'm trying to write a simple program that reads text from standard input
and writes text to standard output. The source code is as follows:

#!/usr/bin/env ruby
text = ""
while (line = gets)
text+=line
end
print text.reverse

Now I want to execute it on the Windows XP box with a pipe to redirect
results so I know that:

reverse.rb sample.txt | reverse.rb

will show me (on the screen be default) the contents of sample.txt file
in non-reversed way.
I'm executing above command line and getting this:

reverse.rb:9:in 'gets': Bad file descriptor (Errno:EBADF)

Do you have any ideas why it doesn't work?

Thanks in advance for any help!

--
Pawel Radecki
m: +48 695 34-64-76
e: pawel.j.radecki@gmail.com
w: http://radeckimarch.blo...

9 Answers

7stud --

11/25/2007 12:19:00 AM

Pawel Radecki wrote:
> Hello everybody!
>
> I'm trying to write a simple program that reads text from standard input
> and writes text to standard output. The source code is as follows:
>
> #!/usr/bin/env ruby
> text = ""
> while (line = gets)
> text+=line
> end
> print text.reverse
>
>
> Now I want to execute it on the Windows XP box with a pipe to redirect
> results so I know that:
>
> reverse.rb sample.txt | reverse.rb
>
> will show me (on the screen be default) the contents of sample.txt file
> in non-reversed way.
> I'm executing above command line and getting this:
>
> reverse.rb:9:in 'gets': Bad file descriptor (Errno:EBADF)
>
>
> Do you have any ideas why it doesn't work?
>
> Thanks in advance for any help!

When I get that error, it usually means that I am trying to read(e.g.
gets) from something that is opened for writing only. I'm not sure how
knowing that is useful in this case.

Isn't the command:

reverse.rb sample.txt | reverse.rb

equivalent to:

cat sample.txt

??
--
Posted via http://www.ruby-....

7stud --

11/25/2007 12:22:00 AM

I forgot to say, your command works for me on mac os x(unix):

$ cat data.txt
hello world
goodbye

$ r5test.rb data.txt | r5test.rb
hello world
goodbye

$
--
Posted via http://www.ruby-....

7stud --

11/25/2007 12:25:00 AM

7stud -- wrote:
> I forgot to say, your command works for me on mac os x(unix):
>
> $ cat data.txt
> hello world
> goodbye
>
> $ r5test.rb data.txt | r5test.rb
> hello world
> goodbye
>
> $

This probably better illustrates what I'm seeing:

$ cat data.txt
hello world
goodbye
$ r5test.rb data.txt

eybdoog
dlrow olleh$ r5test.rb data.txt | r5test.rb
hello world
goodbye
$

--
Posted via http://www.ruby-....

MonkeeSage

11/25/2007 5:18:00 AM

On Nov 24, 10:52 am, Pawel Radecki <pawel.j.rade...@gmail.com> wrote:

> Now I want to execute it on the Windows XP box with a pipe to redirect
> results so I know that:
>
> reverse.rb sample.txt | reverse.rb

Well, you've defined reverse.rb to read from stdin, but you're passing
it a file with no stdin. I think in XP there is a "type" command that
does what "cat" does on posix systems (outputs contents of file to
stdout), so I think you want this:

type sample.txt | reverse.rb | reverse.rb

I don't have an XP box to test on, but that works with "cat" on linux.
(Ps. Does XP's cmd.exe support pipes "|"? Or are you using cygwin or
something similar? (If so, you may have a version of "cat"
available.))

Regards,
Jordan

7stud --

11/25/2007 5:31:00 AM

Jordan Callicoat wrote:
> Well, you've defined reverse.rb to read from stdin,

Read the documentation for gets.

--
Posted via http://www.ruby-....

MonkeeSage

11/25/2007 6:59:00 AM

On Nov 24, 11:30 pm, 7stud -- <bbxx789_0...@yahoo.com> wrote:

> Read the documentation for gets.

Yeah, I probably should RTFM before I reply, heh.

> Returns (and assigns to +$_+) the next line from the list of files
> in +ARGV+ (or +$*+), or from standard input if no files are present
> on the command line.

Doh.

Regards,
Jordan

TerryP

11/25/2007 7:12:00 AM

Pawel Radecki wrote:
>
> #!/usr/bin/env ruby
> text = ""
> while (line = gets)
> text+=line
> end
> print text.reverse
>

Interestingly it seems to work perfectly fine here,

Terry@Dixie$ ruby --version
7:10
ruby 1.8.6 (2007-03-13 patchlevel 0) [i386-freebsd6]
Terry@Dixie$
7:11

botp

11/26/2007 1:25:00 AM

On Nov 25, 2007 12:52 AM, Pawel Radecki >
> reverse.rb:9:in 'gets': Bad file descriptor (Errno:EBADF)
> Do you have any ideas why it doesn't work?

>ruby -v
ruby 1.8.6 (2007-09-24 patchlevel 111) [i386-mswin32]

>ruby reverse.rb sample.txt | ruby reverse.rb
testing only

kind regards -botp

BeeSting Alergy

11/3/2013 6:17:00 PM

Tom the Lesser wrote:
> On Saturday, November 2, 2013 4:43:38 PM UTC-4, BeeSting Alergy wrote:
> > Is there ANYWHERE in the 1st Amendment that says anything about
> > "Separation of Church and State", blockhead?
> >
> > I see that you're too chickenshit...
>
> Wow. Because it took me 16 hours to reply to your stupid posts, I'm
> a "chicketshit"?

Wow. Are you stupid. I wasn't talking about a reply, you dumb piece of
shit. I was talking about this: Is there ANYWHERE in the 1st Amendment
that says anything about "Separation of Church and State", blockhead?

> I have a Life you know. I don't live on Usenet like some of your
> far-right KooKs do.

I've read enuf posts from you to know that YOU DO live on USENET.

> HA HA!!!

You find that you don't have a life funny, do you?

> > ... to actually post the text.
>
> It isn't the text, you willfully-ignorant and -stupid Ko0K. It is
> the concept.

Well, why did YOU bring up the 1st Amendment & "Separation of Church
and State"?

> Did you find the Right to Privacy our U.S. Supreme Court has
> repeatedly ruled is Constituional-protected yet?

Changing the subject is a sign of a moron & a coward, Tom the Lesser.

<*moronic rantings from a ne'er?do?well clipped*>

Repeating my question: Is there ANYWHERE in the 1st Amendment that says
anything about "Separation of Church and State", shit4brains?

Don't change the subject this time, idiot.

Just so you know.

comp.lang.ruby

Piping problem

Pawel Radecki

7stud --

7stud --

7stud --

MonkeeSage

7stud --

MonkeeSage

TerryP

botp

BeeSting Alergy

x Login to ForumsZone