[Ruby] Launching script/runner from within Rails

[Mike Mondragon]

I couldn't get rmagick to install onto a FreeBSD box so I just use the
real Image Magic composite program to process an image.  Page 141 of
the PickAxe book shows an exec/wait example for long running processes
and that's what I use.  The output still goes to standard out.  How
would I control output of the long running process in such a way as
the back tick style?  Or is there a way to wait on a subprocess spun
from the back tick?

wm="/usr/bin/composite -gravity southeast -watermark 25 #{wmimg}
#{inimg} #{outimg}"
exec(wm) if fork.nil?
Process.wait