Just another Referrer script (php)

I've seen some scripts lately, using API or python... This might be more user friendly, pure php.
It leaves referrer link, also you can set your link in user-agent.
Links will be echoed when script finish visiting sites, and each link will show server status code so you know what passed (200), what is not existing (404), blocked (403), too many requests (429), server error (5xx) etc

I've tested it with 2000 links to some wordpress site,
with batch size 10 takes a bit less than 2 minutes,
with batch size 20 it took 1 minute to go through 2000 links,
tried 35 and errors 429 started (too many requests). Test it, play with it, see the limits of your server and adjust accordingly.

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