how to install magento community channel on localhost

I was trying to install module in magento community manager on localhost magento system, but it shows me an error:

connect error: the 'community' channel is not installed. please use the mage shell script to install the 'community' channel.

after some searching I found this:
https://gist.github.com/americkson/1373556

just open command line, go to your magento root folder and type command:

mage channel-add http://connect20.magentocommerce.com/community