Rob Sewell uses Powershell to add a Powershell job step to a set of existing SQL Agent jobs:
I put all of our jobs that I required on the estate into a variable called $Jobs. (You will need to fill the $Servers variable with the names of your instances, maybe from a database or CMS or a text file and of course you can add more logic to filter those servers as required.
$Jobs = (Get-SQLAgentJob -ServerInstance $Servers).Where{$_.Name -like '*PartOfNameOfJob*' -and $_.IsEnabled -eq $true}Of course to add a PowerShell Job step the target server needs to be SQL 2008 or higher. If you have an estate with older versions it is worth creating a SMO server object (you can use a snippet) and checking the version and then getting the jobs like this
Click through for the process.