Re: "unset var" pops var off variable stack instead of unsetting it

[Greg Wooledge]

On Fri, Mar 17, 2017 at 09:51:34PM +0000, Stephane Chazelas wrote:
> Then, the "unset", instead of unsetting IFS, actually pops a
> layer off the stack.

> Credits to Dan Douglas
> (https://www.mail-archive.com/miros-mksh@mirbsd.org/msg00707.html)
> for finding the bug. He did find a use for it though (get the
> value of a variable from the caller's scope).

Isn't this exactly the same as the "upvar" trick that Freddy Vulto
discovered?  http://www.fvue.nl/wiki/Bash:_Passing_variables_by_reference