On Fri, Aug 17, 2007, John Joyce wrote:
> Wow, seems that you can use double-quoted string style substitution  
> for backtick system calls.
> 
> say we make a list of some files:
>  ls = Dir.glob('*.doc')
>  some_file = ls[2]
> 
> on OS X there is the really convenient 'open' tool available at the  
> command line for example.
> `open #{some_file}`
> 
> Whatever application is set to default for opening .doc files will be  
> called to open the file.
> That's not the point as much as system calls via back ticks can be  
> sent variables and expressions from a Ruby script!
> Very convenient!

For added fun, try string interpolation inside regular expressions!

haystack = "foobarbaz"
needle = "bar"

haystack =~ /#{needle}/
=> 3

yeah :D