Command Line Processing / Pipes

ruby-talk
1

Hi Chris,

Sorry, I forgot about 'cat' being a non-standard cmd. It's on this
machine as part of Cygwin. The one liner you gave me works great. It can
accept filenames as arguments and STDIN via a pipe. Howerver, what I am
going to be doing is too complex for a one line script so I will need to
put it in a .rb file. I thought the equivalent of the '-n -e "print"'
one liner would be:

  while gets()
    print
  end

but, when I put this in a file called parser.rb and try

  type input.txt | parser.rb

I get the following:

  The process tried to write to a nonexistent pipe.
  c:/scripts/parser.rb:1:in `gets': Bad file descriptor
(Errno::EBADF)
          from c:/scripts/parser.rb:1

Thanks,
Stu

···

-----Original Message-----
From: list-bounce@example.com [mailto:list-bounce@example.com] On Behalf
Of Chris
Sent: 18 May 2006 14:23
To: ruby-talk ML
Subject: Re: Command Line Processing / Pipes

The following works on Win2k with ruby 1.8.2 (2004-12-25) [i386-mswin32]

type save_sql_env.txt | ruby -n -e "print"

I use 'type' as 'cat' is not a windows command in Win2k

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2

Maybe its a Cygwin thing, the following:

type subseq.rb | ruby pipe-test.rb

works fine for me.

pipe-test.rb is :
=begin
can pipe to scipt on Win ??
i.e. dos>type file.txt | ruby -w pipe-test.rb
=end
while gets()
   print
end

Is the ruby a Cygwin build?

···

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

3

What happens if you do:

type input.txt | ruby parser.rb

?

I think the point may be that you have to call the ruby interpreter
explicitly, rather than relying on windows file associations to do the
right thing when there's a pipe involved.

-A

···

On 5/18/06, Stuart Holden <Stuart.Holden@baring-asset.com> wrote:

Hi Chris,

Sorry, I forgot about 'cat' being a non-standard cmd. It's on this
machine as part of Cygwin. The one liner you gave me works great. It can
accept filenames as arguments and STDIN via a pipe. Howerver, what I am
going to be doing is too complex for a one line script so I will need to
put it in a .rb file. I thought the equivalent of the '-n -e "print"'
one liner would be:

        while gets()
                print
        end

but, when I put this in a file called parser.rb and try

        type input.txt | parser.rb

I get the following:

        The process tried to write to a nonexistent pipe.
        c:/scripts/parser.rb:1:in `gets': Bad file descriptor
(Errno::EBADF)
          from c:/scripts/parser.rb:1

Thanks,
Stu

4

It's getting to ruby if a ruby exception is being thrown.

Does it work w/ perl or any other language? (just curious) I would
think that it woudlnt.

···

On 5/18/06, A LeDonne <aledonne.listmail@gmail.com> wrote:

On 5/18/06, Stuart Holden <Stuart.Holden@baring-asset.com> wrote:
> Hi Chris,
>
> Sorry, I forgot about 'cat' being a non-standard cmd. It's on this
> machine as part of Cygwin. The one liner you gave me works great. It can
> accept filenames as arguments and STDIN via a pipe. Howerver, what I am
> going to be doing is too complex for a one line script so I will need to
> put it in a .rb file. I thought the equivalent of the '-n -e "print"'
> one liner would be:
>
> while gets()
> print
> end
>
> but, when I put this in a file called parser.rb and try
>
> type input.txt | parser.rb
>
> I get the following:
>
> The process tried to write to a nonexistent pipe.
> c:/scripts/parser.rb:1:in `gets': Bad file descriptor
> (Errno::EBADF)
> from c:/scripts/parser.rb:1
>
> Thanks,
> Stu
>

What happens if you do:

type input.txt | ruby parser.rb

?

I think the point may be that you have to call the ruby interpreter
explicitly, rather than relying on windows file associations to do the
right thing when there's a pipe involved.

-A

5

A LeDonne schrieb:

What happens if you do:

type input.txt | ruby parser.rb

Thank you, this did it for me on Windows 2000 with the one click installer:

   type r.rb | r.rb
   r.rb:1:in `readlines': Bad file descriptor (Errno::EBADF)

   type r.rb | ruby r.rb
   ["p ARGF.readlines\n"]

   r.rb r.rb
   ["p ARGF.readlines\n"]

Regards,
Pit