From: Robert Klemme <shortcutter@...>
Date: 2006-08-10T19:05:11+09:00
Subject: Re: access built-in shell commands like 'history' or 'fc'

On 09.08.2006 21:51, bwv549 wrote:
>> Could it be that Ruby is using a different shell than you are used to?
>> I think it uses /bin/sh by default (not sure).
> 
> Perhaps that is part of it.  However, on this suggestion, I entered the
> suggested shell (/bin/sh).  However, the behavior hasn't changed,
> although the 'history' command works fine in this shell.
> 
> Just for reference, this is what I get when checking what this shell
> is:
> 
>   % /bin/sh --version
>     GNU bash, version 3.1.17(1)-release (i486-pc-linux-gnu)
>     Copyright (C) 2005 Free Software Foundation, Inc.
> 
> I'm on Ubuntu 6.X, just for reference.

There is really no point in accessing the history of the shell because 
what you likely want is the history of the *invoking* shell, i.e. the 
one that started your ruby interpreter.  AFAIK there is no way to access 
that history.  If you want to work with that you can do this at the 
shell prompt.

history | ruby -e '...'

Your example with "pwd" worked because "pwd" is also an external program 
(try it out with "type -a pwd").  But you can access PWD much easier 
from inside Ruby:

12:03:59 [~]: ruby -e 'puts Dir.pwd, ENV["PWD"]'
/cygdrive/w
/cygdrive/w

Kind regards

	robert