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Re: foo | tee /dev/stderr | bar # << thanks!
From: |
Greg Wooledge |
Subject: |
Re: foo | tee /dev/stderr | bar # << thanks! |
Date: |
Tue, 7 Jul 2020 07:41:51 -0400 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
On Mon, Jul 06, 2020 at 09:45:59PM -0400, Dale R. Worley wrote:
> bug-bash@trodman.com writes:
> > foo | tee >(cat >&2) | bar
>
> I do wonder how portable >( ... ) is in practice, versus the portability
> of /dev/stderr. Maybe I worry about the former because I'm not
> practiced in named-FIFO programming and so think of it as non-universal.
On Linux and BSD systems, >( ) will use a /dev/fd/ entry. On most
commercial Unix systems, where /dev/fd/ does not exist, it will use a
named pipe in /var/tmp. On a hypothetical system where neither one is
available (Microsoft Windows?), I believe it may use a temp file. That
decision is made at bash's compile time.
The semantics of /dev/fd/* and named pipes are not quite identical, so
if you're relying on some very *special* mechanisms, then there could
indeed be portability issues. For most scripts, however, it shouldn't
matter.