On 04/09/2021, ropers <ropers@gmail.com> wrote:
> On 04/09/2021, Marc Chantreux <mc@unistra.fr> wrote:
>> Another solution is to write commands for this kind of tasks:
>>
>> <<\. cat > ~/x
>> #! /bin/ksh
>>
>> sed -r 's/a/&\
>> /g'
>> .
>
> Wait, hold up, I'm not familiar with this input redirection idiom.
> Could you explain? Why the double <, and why does it not work with a single
> <?
> Also, could you explain the escaped period?[0] This is very hard to
> google.
I've realised the <<char redirection is a Here Document, which is very
googleable. (Silly me. My excuse --that I'm sticking to-- is that
the order and lack of whitespace also threw me, as I've more often
seen this put thus:
cat << HERE > ~/x)
But I still don't understand why you escaped the dot. Is that just an
overly cautious hypercorrection, or is there some reason I should
escape periods in such cases? An unescaped full stop works fine for
me.
Ian
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