Powershell Remove-Item IF file already exists after Copy-item

Question

I need to add a safety net in my script. I'm trying to do a copy job based on a list of users provided through a txt file. Copy the files from that users home directory to a new location. Once the files are copied, check if the file exists in the new location. If yes, then Remove-Item.

Can someone help me? I just don't know how to implement the "if file exists" logic.

$username = Get-Content '.\users.txt'
foreach ($un in $username)
{
  $dest = "\\server\homedirs\$un\redirectedfolders"
  $source = "\\server\homedirs\$un"
  New-Item -ItemType Directory -Path $dest\documents, $dest\desktop

  Get-ChildItem $source\documents -Recurse -Exclude '*.msg' | Copy-Item -Destination $dest\documents
  Get-ChildItem $source\desktop -Recurse -Exclude '*.msg' | Copy-Item -Destination $dest\desktop

  Get-ChildItem $source\mydocuments, $source\desktop -Recurse -Exclude '*.msg' | Remove-Item -Recurse
}

Answer 1

The shortest way to delete file if it doesn't exist is NOT to use Test-Path but:

rm my_file.zip -ea ig

This is short version of

rm my_file.zip -ErrorAction Ignore

which is much more readable and more DRY then

if (Test-Path my_file.zip) { rm my_file.zip }

Answer 2

To answer your question per se, you can do it like this:

Get-ChildItem $source\mydocuments, $source\desktop -Recurse -Exclude '*.msg' | %{
  if (Test-Path ($_. -replace "^$([regex]::escape($source))","$dest")) {
    Remove-Item $_ -Recurse
  }
}

• Test-Path returns $true if the file at the given path exists, otherwise $false.
• $_ -replace "^$([regex]::escape($source))","$dest" converts the path of each source item you're enumerating with the corresponding destination path, by replacing $source at the beginning of the path with $dest.
• The basic regex for the first argument to the -replace operator is ^$source (which means "match the value of $source at the beginning of the string"). However, you need to use [regex]::escape in case $source contains any regex special characters, which is in fact extremely likely with Windows paths, since they contain backslashes. For example, the value you've given here for $source contains \s, which in a regex means "any whitespace character". $([regex]::escape($source)) will interpolate the value of $source with any regex special characters properly escaped, so that you're matching the explicit value.

That said, if your purpose is to copy each item to a new location, and remove the original only if the copy to the new location is successful, it seems like you're reinventing the wheel. Why not just use Move-Item instead of Copy-Item?

---

Not directly related to the question, but rather than repeating the same command for each subdirectory, you can use a foreach loop:

foreach ($subdir in (echo documents desktop)) {
  # Whatever command you end up using to copy or move the items, 
  # using "$source\$subdir" and "$dest\$subdir" as the paths
}