From: Mark Hubbart <discordantus@...>
Date: 2005-06-07T05:44:29+09:00
Subject: Re: 'gets' has been hijacked

On 6/6/05, James Edward Gray II <james@grayproductions.net> wrote:
> On Jun 6, 2005, at 2:31 PM, Pete Elmore wrote:
> 
> > I was working with a simple script, that unexpectedly broke.  The
> > problem can be reduced to this:
> >
> > pete@robots:~$ cat t.rb
> > #!/usr/bin/env ruby
> > p gets
> > pete@robots:~$ ./t.rb
> > asdf
> > "asdf\n"
> > pete@robots:~$ ./t.rb nonexistent-file
> > ./t.rb:2:in `gets': No such file or directory - nonexistent-file
> > (Errno::ENOENT)
> >         from ./t.rb:2
> >
> > Ah, right, I remember this from the Bad Old Days of Perl: stdin has
> > been stolen.  Is there any way to stop this behavior, like a global
> > I could set or a flag I could pass to ruby?  Couldn't find anything
> > on the man page or in Pickaxe.
> 
> gets() as you're using it calls Kernel.gets(), which basically
> amounts to ARGF.gets().  That's very handy for building Unix filters.

expanding on that: ARGF *is* STDIN when there are no files specified:

mark@eMac% ruby -e'p ARGF.fileno == STDIN.fileno'
true
mark@eMac% ruby -e'p ARGF.fileno == STDIN.fileno' /etc/hosts
false

> If your intention is to read from the keyboard only, just make sure
> call gets() on STDIN with STDIN.gets() or $stdin.gets().
> 
> Hope that helps.
> 
> James Edward Gray II
> 
>