Powershell Strip all directory paths from file - powershell

Question

OK what I am trying to do is make a script that will read each line of a text file, "directory.txt" and export every line that is to a file and not to a directory. Example below.
I'm just trying to remove the paths to directories like "C:\users\"
and keep any path that is to a file like "C:\users\file.txt"
In the test file, Direcory.txt" there will be the following:
C:\path\path\folder\
C:\path\path\file.ext
C:\path\path\path\path\folder
The script will need to read the text file above and export the following line to a new text file.
C:\path\path\file.ext
The batch script equivalent would be the following:
#ECHO OFF
FOR /F %%A IN (directory.txt) DO CALL:NoDir "%%A"
pause
EXIT /B
:NoDir
IF "%~x1" NEQ "" ECHO %~1>>nodir.txt
EXIT /B
Batch script can't handle a file of 400mb so need to use powershell to do it o.0

Answer 1

FTR: The condition if "%~x1" neq "" does not do what you seem to expect. It will match not only folders, but also files without an extension.
Anyway, in PowerShell you'd probably do something like this to list only items that are not directories:
Get-Content \PATH\TO\directory.txt `
| Get-Item `
| Where-Object { -not $_.PSIsContainer } `
| Select-Object FullName

Answer 2

I'm not sure I understand the question (batch example shows all paths), maybe that's what you're looking for:
Get-Content directory.txt | Where-Object {$_ -eq 'C:\path\path\file.ext'}

Answer 3

You didn't say whether you're concerned if they are valid paths or not. The following outputs to the host the lines that are either valid files (using the '-PathType leaf' parameter of the Test-Path cmdlet), or if the last 4 characters of the last item in the path are a dot followed by 3 letters.
$Lines = Get-Content C:\Path\to\file.txt
foreach ( $line in $Lines )
{
if ( (Test-Path $line -PathType leaf) -OR ($line -match "\.\w{3}$") )
{
Write-Host $line
}
}
If you find your file extensions are longer than 3 letters, you can change the regex appropriately ("\.\w{3,4}$" for 4 character extensions, or "\.[\w\d]{3,4}$ to match extensions that are 3 or 4 characters long and might include numbers)
And the one-liner:
Get-Content C:\Path\to\file.txt | % { if ((Test-Path $_ -PathType Leaf) -OR ($_ -match "\.\w{3}$")) { $_ } }