From Field System Programmer Reference Manual (Himwich, 1993):
The pfmed program is used to edit and manipulate the procedure file libraries. It may be started from a shell prompt. A semaphore is used to coordinate access to the procedure libraries between boss and pfmed. This allows procedures to be edited even while they are in use. All changes that a user makes in an active procedure library are saved until the operator exits from pfmed. Then the next time boss is scheduled the changes are picked-up. In order to prevent file handling problems between pfmed and boss there are two special restrictions: the Field System cannot be started or stopped while pfmed is active and operator may not change the active procedure library with either a proc= or schedule= command while pfmed is running.
helpfor a list of available commands.
exitwhen finished so that any changes are applied