Powershell

PowerShell is a  shell-scripting language. It combines command-line speed, the flexibility of scripting, and the power of a GUI-based admin tool.
You should learn it because:

• All the server products that Microsoft is producing now can be managed through PowerShell.
• Performing the tasks like updating an active directory manually may take hours to complete. By using PowerShell you can complete it using a single command in less time.
• Many of the GUI interfaces that Microsoft has been designing for its various products are actually front end interfaces to PowerShell.
• Windows PowerShell Can Reveal “Hidden” Information Not Available in the Admin Center.
• Windows PowerShell is Great at Filtering Data. It lets you do cross-product management.
• PowerShell provides full access to Component Object Model and Windows management instruction, enabling administrators to perform administrative tasks on both local and remote Windows systems as well as WS-Management and Common Information Model enabling management of remote Linux systems and network devices.