one-emacs-frame
A tiny script to check whether to open a new emacs frame or put your file into the existing one.
This script isn't really smart but gets the job done for me. It checks the existing frames on your display and looks for any with the name Emacs in it (triggers also on your current browser tab, or others). I have changed my emacs title a little bit, it's represented in the frametitle variable.
Install
It requires that you have wmctrl installed.
Then just copy the shell script and add it to your PATH. Alternatively, you could also create an alias to call it.