How do I install a Connect 2.0 extension to my local development box without using the /downloader UI? How can I script this in a deployment routine?
Installing via SSH:
Obtain the Connect 2.0 key via Magento Connect:
mage is executable from your Magento root:
chmod +x ./mage
./mage install and paste your extension key immediately after the word 'install' - remove the slash between 'community' and your extension package name. E.g.:
./mage install http://connect20.magentocommerce.com/community OnePica_AvaTax
^ Notice the lack of a slash between 'community' and 'OnePica_AvaTax'.
To script into a deployment - issue the
./mage install command from your build. This should sync all production servers to have record of the community module install which should make removing or upgrading the module in the future scriptable as well (without necessitating a commit to your version control system).
How do I install a Connect 2.0 extension to my local development box without using the /downloader UI?
It allows you to download modules directly using extension keys (1.0 or 2.0). Then move the module files into place.
You can use ./mage which is in your directory root eg:(/var/www/). Give access to mage by entering following command:
sudo chmod 775 mage
Get a magento connect key from the website and install it using the following example. Example magento connect key: http://connect20.magentocommerce.com/community/PACKAGENAME
./mage install http://connect20.magentocommerce.com/community PACKAGENAME
Better variant than the one proposed by kevnk is to use https://www.magentokey.com/
It allows you all same things as freegento, but also you can download any version of extension. You will also get links directly from magentocommerce.com, so it's safer.