From: Herbert Xu <herbert@gondor.apana.org.au>
To: наб <nabijaczleweli@nabijaczleweli.xyz>
Cc: dash@vger.kernel.org
Subject: Re: [PATCH] man: document what happens when IFS= (and when it's not)
Date: Sat, 6 Apr 2024 17:30:36 +0800 [thread overview]
Message-ID: <ZhEWPOt67WBRkkf/@gondor.apana.org.au> (raw)
In-Reply-To: <rgn7yvfaitifvmsx7tsu3bicrcrqjbhkai7jdj6q5ja3ccrq3o@musfjdmv7egg>
On Sat, Apr 22, 2023 at 05:16:21PM +0200, наб wrote:
> A question I just got from a user was "how do I make while read -r l; do
> ...; done < f not strip the initial tabs?". Turns out, the manual is
> silent on this, and POSIX just about implies this behaviour.
> (Indeed, our read is almost verbatim POSIX, and both defer to Field
> Splitting, but our Field Splitting isn't nearly as detailed,
> and thank god.)
> Even POSIX spends just one line describing this pivotal behaviour
> (Issue 8 Draft 2.1 line 75044-75045:
> "2. If the value of IFS is null, field splitting shall have no effect,
> except that if the input is empty the result shall be zero fields.),"
> and when I first encountered this it was also quite surprising to me.
>
> Spell it out explicitly: IFS= means that input is preserved,
> and the default value means whitespace is stripped from the front.
> Drive it home with an example because it's esoteric (and I know from
> that user that they first tried searching for read in the manual,
> but it was not very helpful).
>
> Reported-by: rozbrajaczpoziomow <rozbrajaczpoziomow@gmail.com>
> ---
> src/dash.1 | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
Patch applied. Thanks.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
prev parent reply other threads:[~2024-04-06 9:30 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-22 15:16 [PATCH] man: document what happens when IFS= (and when it's not) наб
2024-04-06 9:30 ` Herbert Xu [this message]
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