Server Core in Windows Server 2008 is being hailed by many as potentially the best feature of Microsoft’s latest operating system. If you’re unfamiliar still with Server Core and what it can provide, prepare yourself for this version of Windows, which arrives with no GUI, no support for many types of managed code and little more than a command-line prompt for console administration.
Even though the meat of the OS has changed quite a bit, the core of it remains relatively the same. This holds true for administering and maintaining your Server Core instances once they’re installed.
Once you’ve installed Server Core on your machine and completed the initial configurations that bring it online, you’ll need a set of command-line tools to install Roles or Role Services. As Server Core doesn’t have any GUI support, those tools are all command-line based.
The main command-line tool you’ll be using to install Roles and Role Services is not the same one you would use in the full version of the OS. For full versions of Windows Server 2008, Microsoft provides a command-line adjunct called servermanagercmd.exe that can manipulate the configuration and install/uninstall components as desired. That tool is easy to use and aligns with most of the functionality you get in the GUI form of Server Manager.
For Server Core, however, things are a little different. The servermanagercmd.exe tool is an executable that relies on managed code, and Server Core does not support that execution. So Microsoft had to create another version of the same tool that didn’t have such needs. Why buy one when you can have two for twice the price?
In Server Core, there are actually two tools you’ll use to list and install your Roles and Role Services. The first, oclist.exe, will list the possible Roles for the server as well as identify those which are currently installed.

Source: SearchWinit