XQuartz is an X Window Server for OS X 10.6 or later.
Background on XQuartz
Apple used to ship an X11 app with OS X but this stopped in OS X 10.6. The XQuartz project was orginally based on the version of X11 include in Mac OS X 10.5 and Apple is a contributor to the XQuartz project.
To install XQuartz on your mac, visit the XQuartz website, download the dmg file. Open the dmg file, and it contains a XQuartz.pkg file - double click on this to start the installer.
Daily use of XQuartz
After opening XQuartz for the first time, I recommend selecting the Keep in Dock option.
You will be presented with an X terminal that can be used to ssh to HPC Linux servers (e.g., Cluster login nodes).
I recommend using syntax similar to the following when using SSH to connect to HPC cluster login nodes. The
-Y option will allow graphics to return back to your computer over SSH (securely).
Note that some graphical work will appear to be very slow if you aren't on a JCU campus. Using RDP is a better alternative for graphical workflows.