Date conversion issue in pipeline

Question

I encountered a bizarre issue with date conversion. Everything is working as expected in my local PowerShell, but something goes wrong when the same code is running in a pipeline. The goal is to capture the date from the title and convert it to a different format.

I have a title like:

$title = "Update 11-02-2024"

I am extracting the date from the title:

$date = ([regex]::Matches($title, '(\d{2}-\d{2}-\d{4})')).Value

Converting the old date to a new format:

$newDate = Get-Date $date -UFormat "%B %d, %Y"

The new date is:

February 11, 2024

This is the right format for me, looks like it is working. When the code is running via the pipeline the result is:

Update November 02, 2024

This is what the pipeline runs:

if ($itemTitle -match 'Update') {
                $date = ([regex]::Matches($itemTitle, '(\d{2}-\d{2}-\d{4})')).Value
                $newDate = Get-Date $date -UFormat "%B %d, %Y"
                $newTitle = $itemTitle.Replace($Matches[0],"Dictionaries Update").Replace($date,$newDate)
                Write-host "The new title is: $newTitle"
            }

The pipeline runs a task that runs the script with the same code. What am I missing?

Answer 1

This difference in parsing behavior likely occurs because the pipeline is being executed on a runner machine with en-US default locale, so the default date format is MM-dd-yyyy.

Use [datetime]::ParseExact to always use a specific format when parsing dates:

$newDate = [datetime]::ParseExact($date, 'dd-MM-yyyy', $null) |Get-Date -UFormat "%B %d, %Y"