Query about problem with updating software

[MR ZenWiz]

On Wed, Aug 3, 2022 at 5:18 PM Bret Busby <bret at busby.net> wrote:
>
:
> I replaced the subdomain names with "old-releases", so
> "archive.ubuntu.com" and "security.ubuntu.com", became
> "old-releases.ubuntu.com", and, most of the errors were eliminated.
>
> What is the difference between using ';' and "&&" in the chained
> command? I do know (or, believe) that the "&&" represents the logical
> "AND", but do not know what the ';'represents, unless it is simply like
> the end of an executable line, like in a 'C' program or a Pascal program.
>
'&&' is the logical AND - the first command must complete without an
error (exit status 0) for the second command to execute.

A ';' means to execute the second command in the string after the
first completes, regardless of exit status. Yes, it is similar to an
embedded end of line in a bash script (it means 'this is the end of
the command it follows').

It is not like C or Pascal because those are compiled languages and
the compiler will issue a syntax error without the necessary ';'. On
the command line, no ';' is required except to separate individual
commands strung together.

HTH.

Mark