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Re: Arithmetic expansion with increments and output redirection
From: |
Ian Neal |
Subject: |
Re: Arithmetic expansion with increments and output redirection |
Date: |
Wed, 24 Apr 2019 07:22:18 -0600 |
On Wed, Apr 24, 2019, 07:12 Chet Ramey <address@hidden> wrote:
> On 4/24/19 8:47 AM, Ian Neal wrote:
>
> > At what point is a subshell being invoked? There's no pipeline, command
> > substitution, coprocess, background process, or explicit () subshell
> here,
> > which are the only cases a subshell should be created. Otherwise, the
> > entire operation should be evaluated by the main shell. Arithmetic
> > expansion is not in that list.
>
> Why would you think that /bin/true would be "evaluated by the main shell?"
> It's not a shell compound command or a builtin, and non-builtin commands
> are run in child processes.
>
Calling what should be a simple fork(); exec(); a "subshell" is a little
disingenuous unless it has its own parameter expansion options, which isn't
true -- if the $((n++)) was on the left side of the file redirection (which
is to say a parameter), it would be expanded by the shell before the
fork(), so why is this true with the redirection itself? What makes that
case so special? I posit that it shouldn't be.
>
- Arithmetic expansion with increments and output redirection, Ian Neal, 2019/04/23
- Re: Arithmetic expansion with increments and output redirection, Robert Elz, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Ian Neal, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Greg Wooledge, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Andreas Schwab, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Chet Ramey, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Chet Ramey, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection,
Ian Neal <=
- Re: Arithmetic expansion with increments and output redirection, Chet Ramey, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Ilkka Virta, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Chet Ramey, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Greg Wooledge, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Ian Neal, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Chet Ramey, 2019/04/24
- Re: Arithmetic expansion with increments and output redirection, Chet Ramey, 2019/04/24