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From: Bart Van Assche <bvanassche@acm.org>
To: Daniel Wagner <dwagner@suse.de>,
	Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Cc: linux-block@vger.kernel.org, Daniel Wagner <wagi@kernel.org>,
	John Meneghini <jmeneghi@redhat.com>
Subject: Re: [PATCH blktests 2/3] common/rc: add _echo() function to trace sysfs attribute writes
Date: Wed, 13 May 2026 10:07:43 -0700	[thread overview]
Message-ID: <3ef4e2a4-c0ec-4040-a4c7-3687ed7e2d93@acm.org> (raw)
In-Reply-To: <a1668df1-a93a-442a-ae95-e015bcbeec17@flourine.local>

On 5/13/26 7:05 AM, Daniel Wagner wrote:
> On Wed, May 13, 2026 at 08:23:25PM +0900, Shin'ichiro Kawasaki wrote:
>> +# Echo a value to a file. This wrapper is used to trace sysfs attribute writes
>> +# when the --cmd-trace option is enabled.
>> +_echo() {
>> +	echo "$1" > "$2"
>> +}
> 
> Stupid question, can't we override the echo function, something like this:
> 
> echo() {
>      builtin echo "$@"
>      builtin echo "$@" >> "/tmp/debug_log.txt"
> }

How can this work since the sysfs/debugfs/configfs attribute is not an
argument of the echo command?

Thanks,

Bart.



  reply	other threads:[~2026-05-13 17:07 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-13 11:23 [PATCH blktests 0/3] introduce command trace feature Shin'ichiro Kawasaki
2026-05-13 11:23 ` [PATCH blktests 1/3] check: add --cmd-trace option Shin'ichiro Kawasaki
2026-05-13 17:08   ` Bart Van Assche
2026-05-13 11:23 ` [PATCH blktests 2/3] common/rc: add _echo() function to trace sysfs attribute writes Shin'ichiro Kawasaki
2026-05-13 14:05   ` Daniel Wagner
2026-05-13 17:07     ` Bart Van Assche [this message]
2026-05-13 17:17   ` Bart Van Assche
2026-05-13 11:23 ` [PATCH blktests 3/3] common/nvme, nvme/rc: use _echo() " Shin'ichiro Kawasaki

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