Magento redirect to temporary site

I want to install my magento in my public_html folder but when someone visits my domain, I want it to redirect to my old website while I build my new website.
How is this possible in magento 1.9.2.3?

This tutorial should be helpful:
http://blog.chapagain.com.np/magento...ect-functions/

There might also be redirect extensions that'll work for your store:)

Good luck!

Plan is the following:
1. clear cache (just delete your folder {magento_root}/var/cache/*)
2. go to your DB to the table core_config_data - find there base/secure/url and base/unsecure/url. Make sure that these cells have the name of your site.