The 1.0 version of yooShell for Mac was provided as a free download on our website. The software lies within Theming Tools, more precisely Multiple Desktops.
From the developer:
yooShell removes the barrier between FileMaker and the rest of your system, giving you complete access to the command line. yooShell allows you to call external commands, scripts, and applications. Command output is returned to FileMaker. With yooShell you can inspect and configure the system, find and manipulate files and folders, and use almost any sort of external utility or application, all from within FileMaker.
You may want to check out more software for Mac, such as Occurrence Selector, which might be related to yooShell.