Re: Command Languages Versus Programming Languages

On Sat, 30 Mar 2024 01:30:53 +0100, Janis Papanagnou wrote:

Besides the naming, keep in mind that there's a semantical differences
between a "command", a "built-in command", and "shell construct". An
example where you can observe operational differences is:
  '/bin/test' and '/bin/['
  'test' and '['
  '[['
where (for example) the latter does not need quoting.

I know that there are places in POSIX shells where the usual rules for
interpretation of special-substitution markers are altered or suspended.
But those situations are always delimited in some special way (distinctive
syntactic constructs or reserved words). Throughout the entire rest of the
language, the principles I have described still apply.