According to the city to the site for the station, seeking ideas

According to the city to the site to do sub-station, seeking ideas.
Title, a site to be based on the city to do sub-stations, for example: The main station is www.xxx.com, Beijing station is bj.xxx.com similar to the sub-station technology, how to achieve? My station is PHP plus Mysql,apache server. Tutorial.
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Sub-station good to do, the key is your website content display way, each city station content certainly is not the same, also certainly will have partial same, this part is how manage, as for sub station, Apache can do it
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Apply for a domain name WWW.XXX.COM
Then add a pan domain name resolution in the Domain management office

and open Urlrewrite in Apache.

And then add the rewrite rules to the htccess.

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