Loading the SharePoint Snapin can be done using the following:
Add-PSSnapin "Microsoft.SharePoint.PowerShell"
This only works in the 64bit version of PowerShell. If the window says "Windows PowerShell (x86)" in the title you are using the incorrect version.
If the Snap-In is already loaded, the code above will cause an error. Using the following will load only if necessary, which can be used in Cmdlets/functions:
if ((Get-PSSnapin "Microsoft.SharePoint.PowerShell" -ErrorAction SilentlyContinue) -eq $null)
{
Add-PSSnapin "Microsoft.SharePoint.PowerShell"
}
Alternatively, if you start the SharePoint Management Shell, it will automatically include the Snap-In.
To get a list of all the available SharePoint Cmdlets, run the following:
Get-Command -Module Microsoft.SharePoint.PowerShell