Command Line Processing / Pipes

ruby-talk
1

The one liners mentioned below both work for me. I encounter the
problems only when I put the ruby in a script file.

···

-----Original Message-----
From: Robert Klemme [mailto:shortcutter@googlemail.com]
Sent: 18 May 2006 16:06
To: ruby-talk ML
Subject: Re: Command Line Processing / Pipes

2006/5/18, Stuart Holden <Stuart.Holden@baring-asset.com>:

Hi,

I'm trying to create a script that that is flexible enough to accept
input that is read from a file whose filename is passed as a command
line argument, or from STDIN via a pipe.
(This is on a WinXP platform rather than Unix)

By way of a simple example, I want both of the following to produce

the

same results:

        1: myScript.rb *.txt
2: cat *.txt | myScript.rb

I have had some joy with the first approach...

                while line = ARGF.gets
                        #-- Do the interesting stuff here... or just
print the line.
                        print line
                end

However, I cannot get anything to work for the pipe approach. I

thought

that this would handle piped along STDIN

                while gets()
                        line = $_
                        print line
                end

but it chucks the following error:

                U:\dev\WM&CAPS\capsfiles>cat testfile.caps | caps.rb
                c:/scripts/caps.rb:1:in `gets': Bad file descriptor
(Errno::EBADF)
                        from c:/scripts/caps.rb:1

Works for me:

17:02:50 [~]: ruby -e 'while l=gets; p l; end' x
"foo\n"
17:03:07 [~]: cat x | ruby -e 'while l=gets; p l; end'
"foo\n"
17:03:12 [~]: uname -a
CYGWIN_NT-5.2-WOW64 PDBXPWSRK38 1.5.19(0.150/4/2) 2006-01-20 13:28 i686
Cygwin
17:03:16 [~]: ruby -v
ruby 1.8.4 (2005-12-24) [i386-cygwin]

I guess, you use the windows installer. I prefer the cygwin version as
it has better unix like behavior. Maybe that's an option for you too.

Kind regards

robert

--
Have a look: Robert K. | Flickr

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