Looks like I'm late to the party. :-)
--- Amir
thumbed via iPhone
> On Oct 8, 2014, at 4:46 PM, Amir Caspi <ceph...@3phase.com> wrote:
>
>> On Oct 8, 2014, at 4:23 PM, Duane Hill <duih...@gmail.com> wrote:
>>
>> No. && is a way of chaining commands together. Your cron says run
>> sa-update and then restart spamd. In other words, when sa-update
>> finishes running, regardless if there was an update applied or not,
>> restart spamd.
>
> Unless I am mistaken, I believe this is not correct. On *nix systems, && is
> the logical "and" operator, and it can be used to chain commands as
> dependencies. && short-circuits on failure, so if the first command returns
> zero, the "and" would fail and the second command never runs. The second
> command is only evaluated if the first returns non-zero ("true"). Hence,
> spamd is restarted only if sa-update actually loads an update, and not
> otherwise.
>
> This is the same reason why you can also see commands like:
> do_this || die
> in perl scripts, because the logical "or" operator || will short-circuit on
> success, hence the "fallback" command never gets run if the first one
> succeeded.
>
