From: Sea&Gull <v@...>
Date: 2005-09-14T00:31:32+09:00
Subject: Re: reopening stdin

Ara.T.Howard wrote:
> On Tue, 13 Sep 2005, Sea&Gull wrote:
> 
>> Hi!
>>
>> I have a script.rb which reads some data from stdin.  Something like 
>> this:
>>
>> bash$ cat file_name | script.rb
>>
>> In script.rb I have:
>>
>> #--------------------
>> fi = $stdin
>>
>> fi.each_line do |l|
>>     #...
>> end
>>
>> --------------------
>>
>> After that script.rb needs to communicate with a user interactively: ask
>> what to do and read the answer from... stdin. Something like:
>>
>> #-------------------
>>
>> print "\nYes/No: "
>> answer = $stdin.gets
>>
>> #-------------------
>>
>> Here I had a problem - I can't read user's answer.  I guess I need 
>> somehow
>> to reopen stdin before calling $stdin.gets but have not found how to 
>> do it
>> correctly.
>>
>> Could you please give me a hint?
> 
> 
> 
> well, here you setup stdin of the script.rb to be a pipe and therefore 
> it has
> no controlling terminal:
> 
>   bash$ cat file_name | script.rb
> 
> so, even if you reopen it it will still be a pipe - you cannot get back 
> at the
> terminal.  i think what you are saying is that you want to open the console
> after reading stdin.  so maybe:
> 
>   harp:~ > cat a.rb
>   print STDIN.read
>   STDIN.reopen '/dev/tty'
>   print STDIN.read
> 
>   harp:~ > printf "42\n" | ruby a.rb
>   42
>   then i type 42 followed by ctrl-d
>   then i type 42 followed by ctrl-d
> 
> hth.
> 
> -a

Yes, it was exactly what I was asking
about (with slightly wrong formulation :-) )

Thanks, you helped me a lot!

--
   S&G