Re: Another 'What's the diff Q" (LDo will like this)

On 2024-09-17, Kenny McCormack <gazelle@shell.xmission.com> wrote:

In article <20240917132221.49@kylheku.com>,
Kaz Kylheku  <643-408-1753@kylheku.com> wrote:

On 2024-09-17, Kenny McCormack <gazelle@shell.xmission.com> wrote:

In article <vccesq$3kjv7$1@dont-email.me>,
Janis Papanagnou  <janis_papanagnou+ng@hotmail.com> wrote:
...

I just thought of something.  Suppose your included text contains both
single and double quotes.  This will not be an issue with <<, but will
require extra effort (more than I care to expend!) with <<<.

>
That's actually the property I like with here-docs; that you can
write your template-like text inside the shell-program text as it
shall (and will) be seen at the target side, both forms of quotes
inclusive.

>
Right.  The point I was making is that this rates as a superiority of <<
over <<< - and answers the question posted in the OP: Is there anything one
can do that the other cannot?

>
Many years ago, I was working on an embedded Linux distro (from
scratch). For text files installed on the target system, like /etc,
I had a Makefile-based thing which could preprocess files with several
preprocessors, based on their suffix. One of the preprocessors was
shell. For those files, what the Makefile did was dynamically
generate a temporary script like this:

>
Perhaps you misread my post.  Perhaps you misread "superiority" as
"inferiority".  I admit that the two words do look pretty similar.

No I didn't misread; but that's what it is. While the <<<
syntax represents a certain kind of improvement in that it doesn't
require weird parsing (line-oriented fetching of data that is out of
band with regard to the phrase structure syntax of the shell language),
it has disadvantages due to the increased complexity of quoting.

If you want to produce some templated text with shell interpolation,
with minimal uncertainties with regard to quoting, <<< is in fact
inferior.

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