Re: Two esoteric zsh questions

[Zefram <zefram@fysh.org>]

Jerry Peek wrote:
>1) Can anyone explain the difference in the following two cases?  The
>first sets a shell variable; the second sets an environment variable.
>In the second, I have to quote the `who`:
>
>	% whoson=`who`
>	% export WHOSON=`who`
>
>I looked through the FAQ and scanned through a change list... but
>didn't spot changes in more recent versions, so I'm asking the list.
>Is the difference a bug, side effect, or feature?

Side effect of the way `export' is defined.  These two commands use
completely different bits of shell grammar.  The first is a variable
assignment, in which field splitting is not performed -- everything
in the word on the RHS of the = is assigned to the variable named.
The second is a simple command; the first word is `export' and the
second is `WHOSON=`who`'.  In the expansion of that second word, the
backquoted section is subjected to field splitting (I think `` and
$() are the only places where zsh does field splitting by default),
which results in a simple command with more than just the two words.
The `export' command looks at each argument in turn and tries to make
an assignment out of it; its second and subsequent arguments in this
case are part of the output of who.

-zefram