Working with WMI - Professional SQL Server 2008 Administration with Windows PowerShell - page 174

Figure 8-15
As shown in Figure 8-16, the 0 return code from the StartService method indicates the agent started
successfully.
Figure 8-16
To verify that the SQLSERVERAGENT service started, run the following command:
Get-WmiObject -class Win32_Service | Where-Object { ($_.Name -like 'SQLSERVERAGENT') }