PS-Services

Check

Get-Service

Get-Service -Name *SQL*

Get-Service -DisplayName *SQL*

Get-Service -ComputerName myServer

Get-Service -Name SQLSERVERAGENT -RequiredServices

Get-Service -Name MSSQLSERVER -DependentServices

Start

Start-Service -Name MSSQLSERVER

Restart

Restart-Service -Name MSSQLSERVER -Force

The -force flag is required because SQLSERVERAGENT is a dependent of MSSQLSERVER

Restart-Service -Name SQLSERVERAGENT

Stop

Stop-Service -Name MSSQLSERVER

Stop-Service -Name *SQL*