powershell: copy date from XML and create a new file - powershell

Question

I have an XMLs with a mask XXXXX-sell-XXXXX.xml, code is:
<?xml version="1.0" encoding="utf-8"?>
<document xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<id>document-20210301-sell</id>
<number>1</number>
<type>a1</type>
<id>document-20210301-sell</id>
<number>2</number>
<type>a1</type>
.....
</document>
I want to copy the newest XML to another folder adding date taken from XML in filename with a mask:
yyyymmdd-sell.xml
My code is not doing a job:
$path1="C:\sell\"
$path2="c:\sell\in\"
Get-ChildItem -Path $path1 -Filter "*-sell-*" |
Where-Object { -not $_.PSIsContainer } |
Sort-Object -Property CreationTime |
Select-Object -Last 1 |
[xml]$xml = Get-Content
$date = $xml.document | Where-Object {$_.id -like "*20210301*"}
Copy-Item -Destination $path2 -PassThru |
Rename-Item -NewName {$Date + "-sell".xml"}

Answer 1

Welcome to StackOverflow, mcq. This might work, sometimes pipes make things complicated:
$path1="C:\sell\"
$path2="c:\sell\in\"
$f = Get-ChildItem -Path $path1 -Filter "*-sell-*" |
Where-Object { -not $_.PSIsContainer } |
Sort-Object -Property CreationTime |
Select-Object -Last 1
[xml]$xml = Get-Content $f
$date = $xml.document.id[0]
#
# get date like yyyymmdd:
#
if($date -match "\d+") {
$date = $matches[0];
}
#
# copy and rename:
#
Copy-Item $f -Destination $path2 -PassThru |
Rename-Item -NewName ($date + "-sell.xml")
With $date -match "\d+", \d is regex (Regular Expression) symbol representing any digit in [0-9] (from 0 to 9), "+" means more than 1 digit, in our case 8 for yyyymmdd numerical value, we capture the date substring in .id value, such as 20210301, 20190925, ...
Please also consult https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_regular_expressions?view=powershell-7.1 to start.