From: "René Scharfe" <l.s.r@web.de>
To: Eric Sunshine <sunshine@sunshineco.com>
Cc: Johannes Sixt <j6t@kdbg.org>,
Philippe Blain <levraiphilippeblain@gmail.com>,
Git Mailing List <git@vger.kernel.org>,
junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH 4/1] t3920: replace two cats with a tee
Date: Sat, 3 Dec 2022 09:43:18 +0100 [thread overview]
Message-ID: <4611a23a-e7e9-6039-5d54-c2f8cadc2f73@web.de> (raw)
In-Reply-To: <CAPig+cQack=pJ04fwEiq81x6+2AAG4ni0Gd4GQgr4FS=PERb_Q@mail.gmail.com>
Am 03.12.22 um 06:09 schrieb Eric Sunshine:
> On Fri, Dec 2, 2022 at 11:51 AM René Scharfe <l.s.r@web.de> wrote:
>> Use tee(1) to replace two calls of cat(1) for writing files with
>> different line endings. That's shorter and spawns less processes.
>> [...]
>> Signed-off-by: René Scharfe <l.s.r@web.de>
>> ---
>> diff --git a/t/t3920-crlf-messages.sh b/t/t3920-crlf-messages.sh
>> @@ -9,8 +9,7 @@ LIB_CRLF_BRANCHES=""
>> create_crlf_ref () {
>> - cat >.crlf-orig-$branch.txt &&
>> - cat .crlf-orig-$branch.txt | append_cr >.crlf-message-$branch.txt &&
>> + tee .crlf-orig-$branch.txt | append_cr >.crlf-message-$branch.txt &&
>
> This feels slightly magical and more difficult to reason about than
> using simple redirection to eliminate the second `cat`. Wouldn't this
> work just as well?
>
> cat >.crlf-orig-$branch.txt &&
> append_cr <.crlf-orig-$branch.txt >.crlf-message-$branch.txt &&
It would work, of course, but this is the exact use case for tee(1). No
repetition, no extra redirection symbols, just an nicely fitting piece
of pipework. Don't fear the tee! ;-)
(I'm delighted to learn from https://en.wikipedia.org/wiki/Tee_(command)
that PowerShell has a tee command as well.)
> (Plus, this avoids introducing `tee` into the test suite, more or
> less. The few existing instances are all from the same test author and
> don't seem particularly legitimate -- they appear to be aids the
> author used while developing the test to be able to watch its output
> as it ran.)
I agree that the tee calls in t1001 and t5523 are unnecessary.
René
next prev parent reply other threads:[~2022-12-03 8:43 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-21 17:58 [PATCH] t3920: don't ignore errors of more than one command with `|| true` Johannes Sixt
2022-11-21 22:56 ` René Scharfe
2022-11-22 0:53 ` Junio C Hamano
2022-11-22 18:28 ` Philippe Blain
2022-11-22 22:24 ` Ævar Arnfjörð Bjarmason
2022-11-22 22:37 ` Johannes Sixt
2022-11-22 22:57 ` Ævar Arnfjörð Bjarmason
2022-11-23 0:55 ` Junio C Hamano
2022-12-02 16:51 ` [PATCH 2/1] t3920: support CR-eating grep René Scharfe
2022-12-02 23:14 ` Philippe Blain
2022-12-03 7:09 ` René Scharfe
2022-12-02 23:32 ` Eric Sunshine
2022-12-03 7:12 ` René Scharfe
2022-12-05 1:08 ` Junio C Hamano
2022-12-05 8:28 ` René Scharfe
2022-12-05 9:32 ` Junio C Hamano
2022-12-05 10:43 ` René Scharfe
2022-12-02 16:51 ` [PATCH 3/1] t3920: simplify redirection of loop output René Scharfe
2022-12-02 16:51 ` [PATCH 4/1] t3920: replace two cats with a tee René Scharfe
2022-12-03 5:09 ` Eric Sunshine
2022-12-03 8:43 ` René Scharfe [this message]
2022-12-03 12:53 ` Ævar Arnfjörð Bjarmason
2022-12-03 17:22 ` René Scharfe
2022-12-04 9:34 ` Ævar Arnfjörð Bjarmason
2022-12-04 16:39 ` Eric Sunshine
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