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

From: Eduardo Bustamante
Subject: Re: [Help-bash] Is there a way to read empty string with `read`?
Date: Mon, 23 May 2016 20:01:10 -0500

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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