From: Duy Nguyen <pclouds@gmail.com>
Date: Wed, 22 Jun 2016 18:41:10 GMT
Subject: Re: [PATCH v6 00/11] Fix icase grep on non-ascii
Message-ID: <CACsJy8BMCjjX7_d73LX8+SiYWA4UUFyU3GGzxSVXMK4xubsKNg@mail.gmail.com>
In-Reply-To: <CAPc5daWEoK4Gp138VPstqwCAX+2K=_gSW98brHjmJYNWK4dkZw@mail.gmail.com>

On Wed, Jun 22, 2016 at 8:36 PM, Junio C Hamano <gitster@pobox.com> wrote:
> On Wed, Jun 22, 2016 at 11:29 AM, Duy Nguyen <pclouds@gmail.com> wrote:
>>
>> Can any shell wizards explain this to me? With this code
>>
>> BS=\\
>> echo ${BS}${BS}
>>
>> Debian's dash returns a single backslash while bash returns two
>> backslashes. Section 2.2.1 [1] does not say anything about one
>> backslash (hidden behind a variable!) after escaping the following one
>> and still eats the one after that..
>>
>> [1] http://pubs.opengroup.org/onlinepubs/009604499/utilities/xcu_chap02.html
>
> I am not a wizard, but is the difference between the shell syntax, or just their
> implementation of builtin-echo?  IOW, how do these three compare?
>
> printf "%s\n" "${BS}${BS}"
> echo "${BS}${BS}"
> echo ${BS}$BS}

Great! printf shows two backslashes while both echo'es show one.
printf "\\\\" behaves like echo though. Doesn't matter, at least I
should be able to make the tests work on Debian dash.
-- 
Duy