"Link Monitor" vs "Check Each Link" and setting up cron jobs

If I understand correctly, the setting “Link Monitor” is what controls the scanning for new links, while the “Check Each Link” setting controls the interval for scanning links that have already been logged into the database to make sure they are still good, etc.

That is correct.

“Check Each Link” provides a text box for entering a time period in hours, i.e. you can have it re-check all existing links every 24 hours. Is there a way to specify a specific time for this to occur, as in, say every 24 hours at 2am?

There is no way to set a specific time. The plugin doesn’t actually check all links at once. It tracks the “last checked” time separately for each link, and checks them once the time since the last check exceeds X hours. So it might check link A at 2am and link B at 4pm.

Does it restart the 24 timer every time I hit the Save Settings button to the time I saved?

No, at least not in the current version.

Run continuously while the Dashboard is open
Run hourly in the background

What is the result if both of these are selected? Or, must “Run continuously…” be selected in order for “Run hourly…” to work?

The plugin has a “worker” routine that finds links that need to be checked and checks them. These two options control when and how often that routine is called.

Run continuously while the Dashboard is open
While you have the Dashboard open, the plugin will automatically run every few minutes, looking for links that need to be checked. If it finds any new links, or links that were last checked more than 24 hours ago, it will check them.

Run hourly in the background
The plugin will use the WordPress Cron API to run the worker routine once per hour. As above, the worker will look for links to check and then check them.

These two options are pretty much independent. Having both enabled means that new links will get checked sooner. Disabling both will disable link monitoring entirely.

Also, I’d actually like to forego both of these options in favor of a cron job that performs a scan in the middle of the night when traffic is lightest. Is there any way to reference the function responsible for conducting this scan using a cron script?

It’s probably doable, but not trivial. You would need to load the entire WordPress environment for the plugin to even work. If you can do that, then calling $ws_link_checker->work() would run the scan ($ws_link_checker is a global variable).

Thanks for the really prompt reply.
Very informative.
Thank you.

These two options are pretty much independent. Having both enabled means that new links will get checked sooner. Disabling both will disable link monitoring entirely.

Do I get it right, if I disable both of “Run continously…” and “run hourly..:” the plugin stops working even if I set a time at “check every link”?

Run continuously while the Dashboard is open
While you have the Dashboard open, the plugin will automatically run every few minutes, looking for links that need to be checked. If it finds any new links, or links that were last checked more than 24 hours ago, it will check them.

Run hourly in the background
The plugin will use the WordPress Cron API to run the worker routine once per hour. As above, the worker will look for links to check and then check them.

Janis, please tell, how can I change setting inside script to make it (worker) work continuously without pausing?

Usually when starting new site, I have 10 000+ broken links which I want to find rapidly. Tried to change settings in admin and inside code, but nothing helped. It takes months before all links will be checked…

Thank you very much for such a great script!