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From: Stephane Chazelas <stephane.chazelas@gmail.com>
To: Harald van Dijk <harald@gigawatt.nl>
Cc: Gioele Barabucci <gioele@svario.it>, dash@vger.kernel.org
Subject: Re: dash: read does not ignore trailing spaces
Date: Thu, 3 Dec 2015 21:17:48 +0000	[thread overview]
Message-ID: <20151203211748.GC9581@chaz.gmail.com> (raw)
In-Reply-To: <5660ADD6.4020308@gigawatt.nl>

2015-12-03 22:02:14 +0100, Harald van Dijk:
>   $ for shell in bash mksh posh zsh; do printf %s: "$shell"; $shell
> -c 'IFS=,; echo a, | { read v; echo "<$v>"; }'; done
>   bash:<a>
>   mksh:<a>
>   posh:<a,>
>   zsh:<a,>
> As far as I can tell, the posh/zsh behaviour is the correct
> behaviour, but I'm not convinced yet my interpretation is correct.

No, that would be the same as for:

set -f

set -- $v

It's meant to split into "a" and "b", not "a", "b" and "". As
":" is meant to be treated as a *delimiter* or *terminator*.

That has been discussed a few times on the austin group mailing

zsh and pdksh (and other descendants of the Forsyth shell) treat it as
separator (and are not compliant), mksh (derived from pdksh)
changed it recently. posh (also based on pdksh) still hasn't changed it.

That's a bit counter-intuitive and means for instance you can't
use $IFS to split variables like $PATH/$LD_LIBRARY_PATH...

In the case of read, it even makes less sense because:

~$ echo a:: | sh -c 'IFS=: read a; echo "$a"'
~$ echo a: | sh -c 'IFS=: read a; echo "$a"'

But that's how it's specified.

So dash is indeed conformant there.


  reply	other threads:[~2015-12-03 21:17 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-02 22:37 dash: read does not ignore trailing spaces Gioele Barabucci
2015-12-02 23:25 ` Jilles Tjoelker
2015-12-03 21:02 ` Harald van Dijk
2015-12-03 21:17   ` Stephane Chazelas [this message]
2015-12-03 21:43     ` Martijn Dekker
2015-12-03 23:04       ` Stephane Chazelas
2015-12-03 23:17         ` Stephane Chazelas
2015-12-04  0:00           ` Stephane Chazelas
2015-12-03 22:26     ` Harald van Dijk
2015-12-04 19:51       ` Harald van Dijk
2016-01-29 12:57         ` Martijn Dekker
2016-06-06  8:48         ` [PATCH v2] builtin: Fix handling of trailing IFS white spaces Herbert Xu
2016-06-06 20:43           ` Harald van Dijk
2016-06-07  9:25             ` [PATCH v3] " Herbert Xu
2016-06-12 10:35               ` Harald van Dijk
2016-06-12 11:06                 ` Herbert Xu
2016-06-12 11:12                   ` Harald van Dijk
2016-06-12 12:17                     ` [PATCH v4] " Herbert Xu
2016-06-19 22:01                       ` Harald van Dijk
2016-06-20  1:28                         ` Herbert Xu

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