Re: pwd; docs, builtins and exec

[Dale Scheetz <dwarf@polaris.net>]

On Thu, 20 Aug 1998, Philip Hands wrote:

> > Reading the info page on pwd says that the command responds to --help and
> > --version options. When executed on a Debian system in a bash shell, the
> > builtin command refuses to accept either option. It also suggests the
> > options -PL which, although accepted, seem to cause no change in the
> > output.
> > 
> > If I 'exec pwd --version' it prints:
> > 
> > pwd (GNU sh-utils) 1.16
> > 
> > and promptly logs me out. (I assume from the "exit" it does?)
> 
> Um,  that's down to the ``exec'' which replaces the shell with pwd, which then 
> exits and logs you out --- try 
> 
>    exec ls
> 
> and it too exits.

Understood.

> 
> BTW my ash behaves exactly the same as bash.  Do you have a path which fails 

No it doesn't.

> to include pwd when running under ash ?
> 
> Oh, just for reference:
> 
>   bash-2.01$ pwd --version
>   bash: pwd: illegal option: --
>   pwd: usage: pwd [-PL]

This is the bash builtin. Note that it rejects the option as illegal.

>   bash-2.01$ /bin/pwd --version
>   pwd (GNU sh-utils) 1.16
>   bash-2.01$ ash
>   $ pwd --version
>   /mirror/tmp/gnome

This is the ash buitin. Note that it accepts the option, but ignores it
and prints the path instead.

>   $ /bin/pwd --version
>   pwd (GNU sh-utils) 1.16
>   $ 

In either case the /bin/pwd --version works fine because it is the GNU
version.

I suppose that since GNU behavior is not declared for shells, and posix
doesn't define the actions of non-posix options, that the diversity in
behavior is acceptable under these standards. It just doesn't seem
valuable to maintain such a confusing situation.

Is there a way to disable the builtins, so that the actual commands are
executed instead? (if, else, and fi are all buitins too aren't they ;-(

Oh well ;-)

Thanks, 

Dwarf
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