I had server is running apache, php and my website. I want to clone HN and made it work parallel with my current website. How can I install arc and point it to subdomain like news.myname.com without messing with current one?
Create a separate VirtualHost in your apache config with a ServerName of news.myname.com, etc. I haven't done this precise configuration before, but Googling brings up howtos like https://httpd.apache.org/docs/2.2/vhosts/examples.html.