KM>> I wonder if the whole idea of a "primary" shell in
the environments
 KM>> is moot. [...]

 DM> Under DOS and Win 3.1, there is a primary command processor that is   
 DM> loaded after the OS itself, and before the GUI.  The distinction is  
 DM> preserved but less important in Win95/98, and absent in WinNT.  It's  
 DM> meaningless under UNIX, which is a multi-user OS that permits each
 DM> user to have their choice of command processor, depending upon
 DM> which are installed.

That's not actually true.  In UNIX, at least since SVR4 and 4.4BSD, the
shell that is directly invoked from login has the responsibility, as
session leader, for dealing with SIGHUP, and all other events that affect
the session as a whole.  So there *is* a distinction made between the first
shell in a session and any subsequent shells.

 ¯ JdeBP ®

--- FleetStreet 1.19 NR