This article is from the MachTen & CodeBuilder FAQ, by Jaime Julca firstname.lastname@example.org with numerous contributions by others.
Yes. Under the UNIX shell you simply type (with * if necessary) the data
file or application name, followed by a CR. Since most users continue to use
Finder in combination with MachTen, the typical way to start a Mac app is by
double-clicking. If you double-click a UNIX application when MachTen is
already running, it will bring the MachTen application to the front;
otherwise, it will start MachTen. Starting Mac apps in Power MachTen is a
little more complicated to set up.