Performing an unattended installation of Exchange 2013 is pretty simple. This is useful if you want to install exchange using custom settings such as renaming the default database or placing the database or log files on separate drives etc.
From the installation media folder open command prompt and use the following command line switches to prepare the Active Directory for Exchange 2013
Setup.exe /PrepareAD /IAcceptExchangeLicensingTerms /OrganizationName “ExchangeOrg”
Once completed run the following
Setup.exe /Mode:install /IAcceptExchangeServerLicenseTerms /r:CA,MB /TargetDir: E:\Exchange /CustomerFeedbackEnabled:False /Mdbname:MBXDB01 /DbFilePath:E:\Databases\MBXDB01.mdb /LogFolderPath:F:\Logs\MBXDB01
Note: If installing Exchange 2013 on multiple servers and you are splitting the Client Access role from the Mailbox role, you must install the first Mailbox server first BEFORE installing a Client Access Server.