gistfile1.txt

# I use this on Linux:

#!/bin/bash
# e - launch emacsclient or server.
ps ax | grep "emacs --daemon" | grep -v "grep"
if [ "$?" -eq "1" ]
then
   /usr/bin/emacs --daemon
fi

/usr/bin/emacsclient -c $@

On OSX, it probably works to do something similar, substituting paths:

/Applications/Emacs.app/Contents/MacOS/bin/emacsclient and
/Applications/Emacs.app/Contents/MacOS/Emacs

but, this is untested.