If you want to install Exchange Server 2013 through command-line the process changed a little bit from the previous version, first is most likely that you are going to use PowerShell instead of command prompt, and for that you need to use .Setup.exe.
The second thing is the Setup.exe instead of the setup.com. If you want to install the mailbox role on an existent Exchange Server 2013 organization you just need to run the following command:
.Setup.exe /mode:install /Role:MB /InstallWindowsComponents /IacceptExchangeServerLicenseTerms
We have also a new switch called /DisableAMFiltering which allows to turn on or off the anti-malware feature!