Re: external versions of sh built-in utilities

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

> For what little it's worth, here's where this silly requirement can be found
> (in case you're still looking for it):
> 
> http://pubs.opengroup.org/onlinepubs/9699919799.2016edition/utilities/V3_chap01
As this is in the "introduction" section and there's a more precise (and more 
sensible) definition in 2.9.1, I would rather file an error with the Austin 
Group than trying to implement the words of 1.6.

To me, it looks like whoever wrote that final paragraph in the introduction 
messed up what I regard as two (or three) sub-categories of regular 
built-in-utilities (remember there are two other categories of "built-ins")
-- alias/cd/ulimit et al, which can't sensibly be implemented externally
-- true/false et al, which may regarded as so vital that you don't want 
   PATH to mess them up and command/type, which you need to be built in to 
   escape a messed up (or malicious) setup of PATH and function definitions 
   (see the second example in the description of the "command" command).