Modify a scheduled task with PowerShell

Question

How can I modify the action step in a scheduled task? We have hundreds of scheduled tasks that point to a particular path and run a PowerShell script. How can we find those tasks and then change the path in the action step without deleting and recreating the entire task?

Solution

Scheduled tasks are contained in C:\Windows\System32\Tasks\ and contain XML files. While the Petri article is a good solution for Windows 8 and Windows Server 2012, that's not a complete solution. This should allow you to find the tasks with a specific command or argument, and replace those.

$computer = "localhost"

$oldCommand = "C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe"
$oldArguments = "-File `"C:\Users\Public\Scripts\oldScript.ps1`""
$newCommand = "C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe"
$newArguments = "-File `"C:\Users\Public\Scripts\newScript.ps1`""

$tasks = Get-ChildItem "\\$computer\c$\Windows\System32\Tasks\" | Where-Object {
    $_.PSIsContainer -eq $false `
    -and `
    (([xml](Get-Content -Path $_.FullName)).Task.Actions.Exec.Command -like $oldCommand) `
    -and `
    (([xml](Get-Content -Path $_.FullName)).Task.Actions.Exec.Arguments -like $oldArguments)
    }

$tasks | ForEach-Object {
    $xml = [xml](Get-Content -Path $_.FullName)
    $xml.Task.Actions.Exec.Command = $newCommand
    $xml.Task.Actions.Exec.Arguments = $newArguments
    $xml.Save($_.FullName)
    }

Comments

[Wutnaut]

Export the tasks as .xml, run a find+replace, then import the tasks.

[Wutnaut]

I saw that you have HUNDREDS of scheduled tasks and found out the scheduled tasks module will only let you export 1 task at a time, so you may find this resource handy, especially since you're already working in PS: petri.co.il/export-scheduled-tasks-using-powershell.htm