From: Eric Hodel <drbrain@...7.net>
Date: 2005-10-27T16:44:17+09:00
Subject: Re: Detection of redirection, possible?

On Oct 26, 2005, at 11:44 PM, Shannon Fang wrote:

> Hi All,
>
> How can I detect a ruby program's stdio has been redirected? I  
> would like to do this:
>
> puts "show message to user"
> $stdin.gets unless $stdin.redirected?
>
> This way, if the program runs normally, it show message and wait  
> for user interaction, if it is redirected to a file, then just puts  
> to that file without wating for user intervention.

I think you want IO#tty?:

$ ruby -e 'p $stdin.tty?'
true
$ ruby -e 'p $stdin.tty?' < /dev/zero
false

-- 
Eric Hodel - drbrain@segment7.net - http://segment7.net
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