Each user accessible operation and functionality is implemented in an action. Menu items and hotkeys all invoke actions. An action is like a function call: it has parameters and a return value.
pcb-rnd actions can be listed
./pcb-rnd --show-actions
A full list of actions can be found in the appendix with detailed desciption of parameters and operations they perform.
Actions are entered on the GUI (typically using the ':' key for getting a command line) and on the stdin using the batch GUI. User scripts call actions with all-lowercase function names.