powershell copy a string in one file to another

can you help me with find a some script to help me to replace a string from one to another file.
for example in test1.xml i have string id=“123”, and i want to copy it to test2.xml instead of id=“1” to be “123”

i tried with some script:

[code]

Original text

$inputFile1 = “C:\ephemeral\file1.xml”

Text to be inserted

$inputFile2 = “C:\ephemeral\file2.xml”

Output file

$outputFile = “C:\ephemeral\file3.txt”

Find where the last tag is

if ((Select-String -Pattern “uid=” -Path $inputFile1 |
select -last 1) -match “:(/>\d+):”)
{
$insertPoint = $Matches[1]
# Build up the output from the various parts
Get-Content -Path $inputFile1 | select -First $insertPoint | Out-File $outputFile
Get-Content -Path $inputFile2 | Out-File $outputFile -Append
Get-Content -Path $inputFile1 | select -Skip $insertPoint | Out-File $outputFile -Append
}[/code]

but i am not sure why he use 2 input and 1 output files. idont get it…

Edited at the request of OP - WA

So, you could parse the XML and actually manipulate it programmatically, versus just doing a replace of a string. Have you worked with structured XML before?

there is no point of doing with xml because i have many pcs with IDs in that xml files, and everyone pc has different UID.
So this is an action that I must do, and something else, but first i must put UID from old config file to another in the same UID string line.

i can with this

Get-ChildItem ‘test.xml’ -Recurse | ForEach {
(Get-Content $_ | ForEach { $_ -replace ‘[MYID]’, ‘MyValue’ }) |
Set-Content $_
}
but how can i use instead of ‘MyValue’ to use UID of another file?