From: Rick DeNatale <rick.denatale@...>
Date: 2007-06-09T23:14:29+09:00
Subject: Re: using ` and the bash source command

On 6/9/07, Kevin Jackson <foamdino@gmail.com> wrote:
> Hi all,
>
> I have this code :
> `source ~/.bash_profile`
>
> As part of a script.  But when this line executes I get a sh: command
> not found.  This looks to me like ruby's ` is running /bin/sh instead
> of /bin/bash
>
> So a bit of searching on google and I discover that it's possible to
> do something like:
> %x{/bin/bash -c "source ~/.bash_profile;"}
>
> This doesn't fail with the command not found, but it doesn't actually
> source the file - so it's fairly useless.
>
> Does anyone have a workaround for getting ruby to exec the bash source
> command correctly?  I think I've tried every combination in the docs
> and nothing seems to work.

Because source isn't a command, it's a bash builtin,

rick@bill:~$ man source
No manual entry for source
rick@bill:~$ which source
rick@bill:~$

An excerpt from man bash

SHELL BUILTIN COMMANDS
      ...
       source filename [arguments]
              Read and execute commands from filename  in  the  current  shell
              environment  and return the exit status of the last command exe‐
              cuted from filename.

The source built-in in bash is roughly equivalent to include in C, or
load in Ruby.

Now I think that:
%x{/bin/bash -c "source ~/.bash_profile;"}
%x{/bin/bash -c "~/.bash_profile;"}

do pretty much the same thing, they will execute ~/.bash_profile

The problem is that most bash profiles are used primarily to set
environment variables within a bash process, any such variables would
only be in the environments of the bash process and it's children, not
the parent process.

What effect were you expecting to see?

-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/