How to match first characters with a powershell script

Question

I am trying to move files to a certain folder if they start with a letter and delete them if they start with anything other than a letter.

My code:

Function moveOrDelete($source, $dest)
{
    $aToZ = '^[a-zA-Z].*'
    $notALetter = '^[^a-zA-Z].*'

    Get-ChildItem -Path $source\$aToZ -Recurse | Move-Item -Destination $dest

    Get-ChildItem -Path $source\$notALetter -Recurse | Remove-Item
}

As I understand it the caret will match on the first character when it's outside of the brackets. In other words, the regex in the $aToZ variable will match anything that begins with a letter. the .* part will allow the rest of the file name to be anything. The caret inside the brackets negates the statement so if the file name begins with anything other than a letter it will match. I can't get it to work and I'm not getting any errors which leads me to believe that my regex is wrong.

I have checked this with online tools including this one: https://regex101.com/ and they check out.

I have also used variations of the regex like ^[a-zA-Z] that don't work. Some patterns like [a-zA-Z]* move the files but it's not the pattern that I want.

Here is how I'm calling the funcion:

moveOrDelete ".\source" ".\dest"

And here are the sample file names I'm using:

a.txt
z.txt
1.txt
.txt

arco444 · Accepted Answer · 2018-09-05 12:55:15Z

2

The -Path argument doesn't understand regular expressions, it takes a string and can perform wildcarding but not complex string processing.

So, you need to check the name of each file against the regex with the -match operator. The following should help:

Function moveOrDelete($source, $dest)
{
    $aToZ = '^[a-zA-Z].*'
    $notALetter = '^[^a-zA-Z].*'
    Get-ChildItem -Path $source -Recurse | Where-Object { $_.name -match $aToZ } | Move-Item -Destination $dest
    Get-ChildItem -Path $source -Recurse | Where-Object { $_.name -match $notALetter } | Remove-Item
}

Here, you need to filter the file names with the Where-Object cmdlet, then pipe to the move or remove.

edited Sep 5, 2018 at 12:55

answered Sep 5, 2018 at 12:48

arco444

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2 Comments

Maximilian Burszley Over a year ago

Your ForEach-Object is unnecessary: you can pipe directly to Remove-Item. The same applies to Move-Item.

tooquick Over a year ago

THANKS!! This fixed it. I ended up piping it like TheIncorribible recommended.

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