cc: [email protected]
Subject: Re: Re: [ast-developers] Reverse redirection / assignment order
--------
> In retrospect, the Bash way makes sense. To force reverse evaluation for the
> redirect first in Bash only requires wrapping with a command group. If the
> redirect evaluates first by default, then reversing that to evaluate an
> assignment first is much harder, since assignments can't precede compound
> commands.
>
> # Hide foo's err in bash
> { var=$(foo) cmd; } 2>/dev/null
>
> versus (e.g. if cmd is a ksh-style function)
>
> # Don't hide foo's err in ksh
> var=$(foo) command eval cmd 2\>/dev/null
> { var=$(foo >&3) cmd 2>/dev/null; } 3>&1
>
> The former is obviously better, at the cost of breaking anything that
> relies on the standard behavior. Apparently nobody's complained in the last 2
> decades.
>
>
I don't get your point.
> { var=$(foo) cmd; } 2>/dev/null
will hide the error in ksh since redirections are done first for compound
commands.
var=$(foo) cmd 2>/dev/null
will not hide assignment errors, but since the assignment is on the {...}
it is done first.
David Korn
[email protected]
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