Ubuntu's PPA

PPA, which represents the personal package Archives, which is the personal packages set
Many packages are not accessible to the official Ubuntu repositories for various reasons. To make it easy for Ubuntu users, Launchpad.net provides a PPA that allows users to build their own repositories and freely upload software . The PPA is also used to test some software that intends to enter the official Ubuntu warehouse, or a new version of some software.
Launchpad is a website set up by Ubuntu parent company Canonical Ltd., a platform that provides maintenance, support, or contact with Ubuntu developers.
For Ubuntu, searching with Https://launchpad.net/ubuntu/+ppas is more accurate
Add Source Address
After Ubuntu 9.10, add the source address, key and so on, just need a simple command to
sudo add-apt-repository ppa:user/ppa-name
ubtuntu10.04 Installing the PPA source for Redis
To https://launchpad.net/ubuntu/+ppas search "Redis-server"
Import the source of this PPA by the instructions above
sudo add-apt-repository ppa:schwuk/redis
Update Source to install Redis, add PPA source equivalent to add those two software sources in the sources list
sudo apt-get update
sudo apt-get install Redis-server

Ubuntu's PPA