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Re: [Help-bash] Is there a way to read empty string with `read`?

From: Peng Yu
Subject: Re: [Help-bash] Is there a way to read empty string with `read`?
Date: Mon, 23 May 2016 21:46:05 -0500

Would it cause any problems with UTF-8 coded tsv input?

On Mon, May 23, 2016 at 8:01 PM, Eduardo Bustamante <address@hidden> wrote:
> By definition, a "text file" should not contain control characters, so
> you're pretty safe with this hack.
> On Mon, May 23, 2016 at 7:12 PM, Peng Yu <address@hidden> wrote:
>> On Mon, May 23, 2016 at 8:45 AM, Greg Wooledge <address@hidden> wrote:
>>> On Mon, May 23, 2016 at 07:18:16AM -0500, Peng Yu wrote:
>>>> Hi, The following code shows that an empty string between two TABs can
>>>> not be captured. Is there a way to let bash read empty strings between
>>>> TABs?
>>> Convert the tab characters to some other character that is not treated
>>> as whitespace by IFS, and which also does not appear in the input data.
>>> echo $'one\ttwo\t\tfour' > testfile
>>> while IFS=$'\002' read -ra array; do
>>>     declare -p array
>>> done < <(tr \\t \\002 < testfile)
>> I have never encountered \\002 in a tsv file. In this sense, this
>> probably should be a reasonable work around. There are explain about
>> \\002 or STX in ascii code doc. However, I am not sure whether it is
>> of much relevance today. Do you have any real case common examples in
>> which these control characters are used in a text file?
>>> Multiple consecutive whitespace characters are treated as a single
>>> delimiter by IFS.  This is by design, as it's what you want 99% of the
>>> time, for input files that have fields padded by whitespace.
>> --
>> Regards,
>> Peng


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