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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 19:12:01 -0500 |
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