On Wed, 4 Sept 2024 at 11:03, Max Nikulin <maniku...@gmail.com> wrote:
> On 04/09/2024 15:17, Thomas Schmitt wrote:
> In /tmp/check_debian_iso line 153:
> sum_from_file=`dd if=$file bs=2048 count=$blocks | $checksummer | head
> -1 | awk '{print $1}'`
> ^---^ SC2086 (info): Double quote to prevent
> globbing and word splitting.
Hi, that particular SC2086 warning can be ignored because the
$1 that it is mistakenly complaining about is awk syntax, and the
shell will not touch that because it is inside single-quotes.
Whether and whether any of $file, $blocks, $checksummer
need to be double quoted is a matter of preference, if their
contents is known to not contain whitespace or globbing
characters. Personally I would use double-quotes there, because
I always double quote expansions like that, unless I actually
want wordsplitting or expansion. I prefer that style, because it
has the benefit of providing a visual cue for the rare cases
that wordsplitting or expansion of the variable content is intended.
And it is visually clearer after the editor applies syntax coloring too.
With all that happening, it seems that shellcheck has missed
modern advice about the backticks. See here:
http://mywiki.wooledge.org/BashFAQ/002
and here:
http://mywiki.wooledge.org/BashFAQ/082
For example, entering
foo=`echo bar`
at shellcheck.net gives:
SC2006 (style): Use $(...) notation instead of legacy backticks `...`.
with explanation at:
https://www.shellcheck.net/wiki/SC2006
