You are looking at a command called turn

turn {object}

You can turn objects.

turn the dial and the object may be scripted to react to you turning it.

read the command called touch
or to have some more forceful influence in the world read the command called push
or more extreme read the command called hit


scripting notes:
This sends out a trigger word 'turn' so you can script your objects thusly:

if target of turn then knobturned;
##knobturned: print "[$actor] squeels and a ket of steam is released";
Code