As far as I know, Linux can only install package from its Repository list.
And there are plenty of repositories out there.
After you have installed/updated the repository list, you can install the package you want.
But... I have no idea how to find a repository list that has the specified version of a package I want to install.
For example, I want to install php55u, not php55w or whatever.
Where/how can I find such a repository list or whatever that contains the php55u so I can have yum install it?
Correct me if I am wrong