From: Robert Klemme <shortcutter@...>
Date: 2011-03-02T22:45:18+09:00
Subject: Re: exec using sh -c or directly running the command, depending on the system

On Wed, Mar 2, 2011 at 2:29 PM, Xavier Noëlle <xavier.noelle@gmail.com> wrote:
> 2011/3/2 Brian Candler <b.candler@pobox.com>:
>> Looks like there was a change in Ruby, where perhaps it now does an
>> optimisation to check for cases where a shell isn't required (e.g. no
>> pipelines or redirection)
>
> That's what I noticed with quoting, but I never managed to take
> advantage of this feature.
> Well, more precisely, I tried to cheat Ruby by quoting every command
> line argument, which works on a system, but not the others (don't know
> if it's a matter of version, system, or something else). What works is
> to append a fake redirection to the command itself, but it's...ugly ^^
>
>> You could make it consistent by using the multi-argument form of exec,
>> which I believe will bypass the shell in all cases:
>
> Works in this case, thanks !
>
> What about the case in which a shell is needed ? Is there a way to
> force Ruby to use a subshell instead of doing everything by itself ?

You can always explicitly invoke the shell.

ruby19 -e 'exec(ENV["SHELL"], "-c", "whatever you like")

Cheers

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/