Scheduling the recurring execution of a powershell script

Jul 11, 2020  

The Windows Task Scheduler can be used to run tasks at predefined intervals, e.g. once a day, and is very much like cron jobs found on other systems.

Running Powershell scripts requires some attention, or nothing will happen when the task scheduler launches it.

Powershell script

I wanted to fetch the contents of a web page every morning, in order to have the data handy without having to do the work manually. So I decided not to use wget for Windows, but instead rely on Powershell’s ability to call directly into .NET:

(new-object System.Net.WebClient).DownloadFile('','D:\Data\bar.txt')

Running this shell script manually will prompt for the execution policy, in order to make sure that I intend to execute the (possibly malicious) script. So scheduling the execution of the script with the Task Scheduler will hang, as I won’t be there to press [Y] to allow for the script to be run.

Starting a Powershell script, bypassing Execution Policy

The solution is to start powershell.exe instead of the *.ps1 script, and provide the -ExecutionPolicy argument in order to configure it to Bypass:

powershell.exe -ExecutionPolicy Bypass C:\scripts\download-foo-bar.ps1