Re: Probably not a bug but I was surprised: $' does not work inside "..." close.

[Greg Wooledge]

On Wed, Mar 17, 2021 at 09:11:48PM -0400, Dale R. Worley wrote:
> I have it encoded in my head that $ inside "..." is respected.  Subtly,
> the $'...' construction is not respected inside "...".

Bash has 5 types of quoting: '...', "...", $'...', $"..." and backslash.

$'...' is a form of quoting, not an expansion.  It won't "work" inside
of another type of quoting, just like '...' will not "work" inside "...".

echo "foo is '$foo'"

In this example, $foo is expanded, despite the fact that there are
single quotes around it, because the single quotes have no meaning in
this context.  They're inside a *different* type of quoting, so they
are just regular literal characters.

The only exception here is backslash, which retains its special powers
when inside "..." or $"...".