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Re: redirections preceded by a word with builtins inconsistent
From: |
Chet Ramey |
Subject: |
Re: redirections preceded by a word with builtins inconsistent |
Date: |
Tue, 24 May 2016 11:23:12 -0400 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 |
On 5/24/16 1:41 AM, Dan Douglas wrote:
>> You don't precede it with an `exec', so it doesn't affect the current
>> shell. So-called `null' commands with redirections are executed in
>> subshells. This is where you need the `exec'.
>
> I know POSIX allows for a subshell but don't know what the point is. I
> was confused by this when I first hit it. The subshell isn't obvious.
It's not that Posix `allows' a subshell, it requires a subshell
environment:
"If there is no command name, any redirections shall be performed in a
subshell environment."
Bash produces a subshell environment by creating a subshell.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU chet@case.edu http://cnswww.cns.cwru.edu/~chet/