The PowerShell command Copy-Item will overwrite a file if it exists by default. This is unless that file is marked Read Only in which case you can use the -Force switch to overwrite the file.

What if you want to only copy the file if it doesn’t exist? Here’s a quick PowerShell script that will complete this task:

$sourceFile = 'c:\temp\something.txt'
$destinationFile = 'c:\temp\1\something.txt'
if (-not (test-path $destinationFile))
{
  $opts = @{'path' = $sourceFile; 'destination' = $destinationFile; 'confirm' = $false}
  copy-item @opts
}
else
{
   $opts = @{'path' = $sourceFile; 'destination' = $destinationFile; 'confirm' = $true}
   copy-item @opts
}