The package link and package unlink commands are fairly new to CommandBox and here's a brief screencast that shows you a real life use case for them. The package link command will create a symlink from your current directory into your CommandBox's system modules folder and reload your shell.
This is perfect to do some quick on-the-fly testing of a module that you're in the middle of developing without requiring you to publish your module or do a full installation every time you make a chance. Just link the module in and you can test live changes as you edit the code.
Even though I didn't show it in the video, you can also use the link command to link your current working directory to a specific target location like a ColdBox or ContentBox app. This also lets you do quick and easy testing of modules inside of a web application as well.
Here's the screencast: