How can I redirect PowerShell output when run from Task Scheduler?

Question 1

Here is the command that worked for me. I didn't like the idea of redirecting the output in the script, since it would make it difficult to run manually.

powershell -windowstyle minimized -c "powershell -c .\myscript.ps1 -verbose >> \\server\myscript.log 2>&1"

Question 2

I use the transcript feature to help with this. Just include it in your code and it outputs all (would be) screen content to a log file.

Start-Transcript -path $LogFile -append

<Body of the script>

Stop-Transcript

Question 3

The following works for me on Windows 7:

 powershell -command c:\temp\pscript.ps1 2>&1 > c:/temp/apickles.log

In the Windows 7 Task Scheduler GUI:

 program = "Powershell"
 arguments = "-command c:\temp\pscript.ps1 2>&1 > c:/temp/apickles.log"

Note that "-file" does not work because all parameters after the file name are interpreted as parameters to the file. Note that "2>&1" redirects the error output to the log file as well. Later versions of PowerShell do this in a slightly different way.

Question 4

A combination of all the previous answers really helped me out...

My problem was that I needed to execute a PowerShell script over WinRM as part of a Packer provisioner, and it kept failing due to rights issues. The way around this is to execute as a scheduled task, but I needed to pass arguments to the script and get the output as well to confirm everything passed.

This snippet worked well for me:

# Generate a unique ID for this execution
$guid = [guid]::NewGuid()
$logFile = "C:\Windows\Temp\$guid.log"

$argument = "-NoProfile -ExecutionPolicy unrestricted -Command ""& {""$ScriptPath"" $ScriptArgs} 2>&1 > $logFile"""

$a = New-ScheduledTaskAction -Execute "powershell.exe" -Argument $argument
Register-ScheduledTask -TaskName $TaskName  -RunLevel Highest -User $username -Password $password -Action $a | Start-ScheduledTask
do {
    Start-Sleep -Seconds 30
    $task = Get-ScheduledTask -TaskName $TaskName
} while ($task.State -eq 4)

The full script can be found here:

https://gist.github.com/dev-rowbot/fa8b8dadf1b3731067a93065db3e1bba

Question 5

I would do:
Create a function to call your script and redirect the output of this function like this:

.ps1:

function test{
    # Your simple script commands
    ls c:\temp -Filter *.JPG
    ls z:\ # Non-existent directory
}

test *> c:\temp\log.txt

Here is the log file:

    Répertoire : C:\temp


Mode                LastWriteTime     Length Name
----                -------------     ------ ----
-a---        07/06/2008     11:06     176275 HPIM1427.JPG
-a---        07/06/2008     11:06      69091 HPIM1428.JPG
-a---        07/06/2008     11:06     174661 HPIM1429.JPG


ls : Lecteur introuvable. Il n'existe aucun lecteur nommé « z ».
Au caractère C:\temp\test.ps1:14 : 1
+ ls z:\ #non existent dir
+ ~~~~~~
    + CategoryInfo          : ObjectNotFound: (z:String) [Get-ChildItem], Driv
   eNotFoundException
    + FullyQualifiedErrorId : DriveNotFound,Microsoft.PowerShell.Commands.GetC
   hildItemCommand

You can control what do you want to output with the new V3 redirection operators:

Do-Something 3> warning.txt  # Writes warning output to warning.txt
Do-Something 4>> verbose.txt # Appends verbose.txt with the verbose output
Do-Something 5>&1            # Writes debug output to the output stream
Do-Something *> out.txt      # Redirects all streams (output, error, warning, verbose, and debug) to out.txt

Question 6

It would be maybe easier to use Start-Transcript in order to log directly to a file:

# Get script name
$ScriptFullPath = $MyInvocation.MyCommand.Path
# Start logging stdout and stderr to file
Start-Transcript -Path "$ScriptFullPath.log" -Append

[Some PowerShell commands]

# Stop logging to file
Stop-Transcript

The log file will be in the same directory as the script.

Question 7

I tested the following on Windows Server 2016, only call powershell once. This way you can have folder names with a space:

Powershell.exe -NoProfile -ExecutionPolicy Bypass -WindowStyle minimized "scriptName.ps1 *>> '\\servername\sharename\folder name with space\logfilename.log'"

Question 8

I'm inspired to write this answer by a comment-question from Anders (How do you add a timestamp?), and by the multiple replies that invoke PowerShell twice, which I would argue is not required. The task scheduler program is clearly "powershell.exe" and for the arguments I would suggest simply:

-noninteractive -c "scriptpath.ps1 *>>logpath.txt"

To keep a file per day, then:

-noninteractive -c "scriptpath.ps1 *>>logpath-$((get-date).ToString('yyyy-MM-dd')).txt"

And if you do want a log file with timestamp, you could remove the second ">" (two indicating append to any existing file) and expand the time format:

-noninteractive -c "scriptpath.ps1 *>logpath-$((get-date).ToString('yyyy-MM-dd_HH-mm-ss-fff')).txt"

Question 9

PowerShell 3 onwards allows individual streams (out, verbose, and error) to be redirected. However, Task Scheduler does not understand them. It's PowerShell that does the redirection.

@cmcginty's solution halfway works, since PowerShell is invoking PowerShell. It only supports standard streams (error and out). If you want to use all streams you need to use:

Program or script: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe

Argument: -windowstyle minimized –NonInteractive –NoProfile -c "powershell -c path_to_ps1.ps1 4>>verbose.log 5>>debug.log"

Start in: path_to_ps1

Question 10

The below sends verbose output to the screen as well as log it to a file.

something you're doing -Verbose 4>&1 | Tee-Object "C:\logs\verb.log" -Append