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From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Subject: Re: [kvm-unit-tests PATCH v3 3/6] arch-run: reduce return code
 ambiguity
Date: Wed, 2 Mar 2016 13:57:00 +0100
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Cc: Andrew Jones <drjones@redhat.com>, kvm@vger.kernel.org
To: Paolo Bonzini <pbonzini@redhat.com>
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2016-03-01 22:29+0100, Paolo Bonzini:
> On 29/02/2016 19:53, Andrew Jones wrote:
>> +	errors=$("${@}" 2>&1 1>&${stdout} | tee >(cat - 1>&2); exit ${PIPESTATUS[0]})
> 
> Whoa! :)  So stdout goes to {stdout} and from there to the real stdout;
> stderr instead is tee'd to stderr and $errors.

Yeah. :)

> Is the "tee" and "cat" necessary?  Can you just use printf somewhat like:

They are, if you want want to improve chances of getting the original
order of stdout and stderr.

> 	# stdout to {stdout}, stderr to $errors
> 	errors=$("$@" 2>&1 1>&${stdout})
> 	ret=$?
> 	printf '%s\n' "$errors" >&2

(Previous version did this any my suggestion was to change it ...)

> ?  Or something like that (for example I'm not sure if you need the \n).

Trying to improve the original solution, What about a bit more
understandable

  errors=$("${@}" 2> >(tee >(cat) >&2) >&$stdout)

?

Which gets rid of some redirections and PIPESTATUS.

> In either case, stdout and stderr can be mixed.

Yes, we can't have a good solution here.

>> +	temp_file RUNTIME_arch_run <(echo "#!/bin/bash"; cat scripts/arch-run.bash "$TEST_DIR/run")
> 
> Please use a pipe instead of a <(...):

(Is it for aesthetic reasons?)

Thanks.