rtcary - First, please excuse me if I am being out of line but please don't do things like this until you FULLY understand what you are doing.
Okay First, adding the -y flag all over the place is asking for trouble. That "-y" automatically answers a question "Yes" that you should really be thinking about before answering, why would it ask you a question at all if the answer doesn't matter enough to answer?
Next, your yum install epel-release and the next line starting with "wget" are doing the same exact thing. Getting the repository linked using the Yellowdog (YUM) command would be my choice here, (of course without that -y).
The "rpm" line installs the repository using the rpm downloaded by the wget statement two lines up that I told you not to do. If you do choose to use the yum statement you won't need to do that (it does happen behind the scenes, but you dont need to run it)
Finally the "yum (-y) update" statement just checks all of your packages to see if new versions of them have been added to any of the repositories you are linked to, that being said theres really no reason you would want to run it twice in a short amount of time. I am on board with running yum update BEFORE you do something like this but not twice.
All these things being said here is what I personally recommend:
yum update all
yum install epel-release
wget
https://centos6.iuscommunity.org/ius-release.rpm (Do you have Centos 6? This link would be different for Centos 7 which is what I thought we were talking about...)
yum install php56u php56u-opcache php56u-xml php56u-mcrypt php56u-gd php56u-devel php56u-mysql php56u-intl php56u-mbstring php56u-bcmath php56u-soap