Emacs, Mac OS X and opening from Shell

["Alberto Simões" <hashashin@gmail.com>]

Dear Emacs users,

I've been an Emacs user for some decades, but never a really emacs hacker.
In the latest months I've been using Sublime for Mac, but I am missing
emacs a lot.

So, in the come back, I am trying to make the emacs command to open an
emacs window, if one is open, or opening a new buffer in the current window
(and focus that buffer if possible).

Currently, my emacs command line is a shell script that looks like this:

   /Applications/Emacs.app/Contents/MacOS/Emacs "$@" &

This, of course, open a new window (although I usually close it, as the
buffers are shared among windows).

Any idea how I can make it behave as I described earlier?

Thank you,
Alberto

-- 
Alberto Simões