Re: Redirecting error message from ${parameter:?word}

[Greg Wooledge]

On Tue, Jan 14, 2020 at 07:17:34PM +0100, Michael Siegel wrote:
> Am 12.01.20 um 07:37 schrieb Eli Schwartz:
> > 
> > It should suffice to use any compound command; the simplest would be to
> > use { cmd; } 2>/dev/null
> > 
> > No subshell needed, which it seems is something the OP cared about.
> 
> Exactly, that's what I was looking for.
> 
> But why does this work? I mean, I get why redirecting the shell's error
> stream works when using a subshell. But how does using a compound
> command lead to masking the expansion error?

Same reason that   { time foo ...; } 2>file   works.

The brace grouping introduces a new redirection context point.  It's
not a whole process, but there's enough *state* involved that you
can have separate file redirections inside vs. outside.

https://mywiki.wooledge.org/BashFAQ/032