From: Glenn Jackman <glennj@...>
Date: 2009-09-04T01:15:24+09:00
Subject: Re: declare a shell alias in a ruby file

At 2009-09-03 11:22AM, "jney" wrote:
>  Hello,
>  
>    I'm trying to declare a shell alias from a ruby file.
>  
>  here is the file test.rb :
>  # begin test.rb
>  `alias world='echo hello'`

you spawn a shell, declare the alias, then the shell exits taking the
alias with it.

>  I'm launching it :
> > ruby test.rb
>  
>  Then launching the alias :
> > world
>  -bash: world: command not found
>  
>  Does anyone know how do i declare a shell alias from a ruby file ?

If you want a child process to make changes to the current process, you
have to make the child tell the parent what to do and then the parent
has to do it.

#### alias.rb outputs shell commands
puts <<END
alias world='echo hello'
END

#### shell evaluates the output of the ruby program
eval $(ruby alias.rb)
world

-- 
Glenn Jackman
    Write a wise saying and your name will live forever. -- Anonymous