While the Magento Download Manager allows you to install extensions through a webpage, the same is possible from command-line. This video-tutorial shows you how to install a Magento extension using a SSH terminal. For this you will need shell-access to your Magento instance.
The following command should be run to initialize the PEAR-command properly:
./pear mage-setup .
With the following command you would install all the latest Magento updates:
./pear install magento-core/Mage_All_Latest
The following would install the Yireo MageBridge Installer. (To upgrade to the actual version you need to obtain a valid license key from our Yireo Shop.)
./pear install magento-community/Jira_MageBridge
The following would upgrade all installed Magento extensions: