In order to execute farm level cmdlets in SharePoint Management Shell you will need to be given Shell Admin access. Even if you are a farm administrator and you have not been given Shell Admin Access, then you won’t be able to execute farm administrative operation using PowerShell. There are lots of operations that you cannot do via the Central Administration GUI and for which you will require Shell Admin Access.
List who has SP Shell Admin Access
Before you get started with addition, it would be good to check who has Shell Admin access using the following PowerShell cmdlet
Let’s check who is in the farm administrator group for http://server
Even though I am a farm administrator, I could not use SharePoint Management Shell to get a list of users who have SPShellAdmin access.
Give user SP Shell Admin Access
To add a user as Shell Admin, use the following PowerShell cmdlet (logged in as the account that has SPShellAdmin access)
Add-SPShellAdmin -username alpesh
Or simply type Add-SpShellAdmin and press enter. You will be prompted to enter the username! Then type get-spshelladmin to see if you have successfully added the user as SPShellAdmin
Remove SP Shell Admin Access for a user
To remove a user as Shell Admin, use the following PowerShell cmdlet
Remove-SPShellAdmin –username alpesh
Or simply type Remove-SPShellAdmin and press enter. You will be prompted to enter the username!