In the last couple of days I have been trying to get a few configurations of ArcGIS for Server set up on Virtual Machines (VM's). Along the way I have spectacularly broken quite a few and had to restart the process. After the second time installing I looked up the silent install documentation and wrote a short batch file to streamline the process.
At the top are a few variables for the installation. Please actually change the password to something halfway secure. At the very least, please change it. Also, you likely will need to change the name of the license file to match yours. Otherwise, I hope this makes your life easier!