Powershell – How to delete empty subfolders with PowerShell

delete-directoryfilepowershellrecursion

I have a share that is a "junk drawer" for end-users. They are able to create folders and subfolders as they see fit. I need to implement a script to delete files created more than 31 days old.

I have that started with Powershell. I need to follow up the file deletion script by deleting subfolders that are now empty. Because of the nesting of subfolders, I need to avoid deleting a subfolder that is empty of files, but has a subfolder below it that contains a file.

For example:

FILE3a is 10 days old. FILE3 is 45 days old.
I want to clean up the structure removing files older than 30 days, and delete empty subfolders.

C:\Junk\subfolder1a\subfolder2a\FILE3a

C:\Junk\subfolder1a\subfolder2a\subfolder3a

C:\Junk\subfolder1a\subfolder2B\FILE3b

Desired result:

Delete: FILE3b, subfolder2B & subfolder3a.
Leave: subfolder1a, subfolder2a, and FILE3a.

I can recursively clean up the files. How do I clean up the subfolders without deleting subfolder1a? (The "Junk" folder will always remain.)

Best Answer

I would do this in two passes - deleting the old files first and then the empty dirs:

Get-ChildItem -recurse | Where {!$_.PSIsContainer -and `
$_.LastWriteTime -lt (get-date).AddDays(-31)} | Remove-Item -whatif

Get-ChildItem -recurse | Where {$_.PSIsContainer -and `
@(Get-ChildItem -Lit $_.Fullname -r | Where {!$_.PSIsContainer}).Length -eq 0} |
Remove-Item -recurse -whatif

This type of operation demos the power of nested pipelines in PowerShell which the second set of commands demonstrates. It uses a nested pipeline to recursively determine if any directory has zero files under it.

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Python – How to check whether a file exists without exceptions

If the reason you're checking is so you can do something like if file_exists: open_it(), it's safer to use a try around the attempt to open it. Checking and then opening risks the file being deleted or moved or something between when you check and when you try to open it.

If you're not planning to open the file immediately, you can use os.path.isfile

Return True if path is an existing regular file. This follows symbolic links, so both islink() and isfile() can be true for the same path.

import os.path
os.path.isfile(fname)

if you need to be sure it's a file.

Starting with Python 3.4, the pathlib module offers an object-oriented approach (backported to pathlib2 in Python 2.7):

from pathlib import Path

my_file = Path("/path/to/file")
if my_file.is_file():
    # file exists

To check a directory, do:

if my_file.is_dir():
    # directory exists

To check whether a Path object exists independently of whether is it a file or directory, use exists():

if my_file.exists():
    # path exists

You can also use resolve(strict=True) in a try block:

try:
    my_abs_path = my_file.resolve(strict=True)
except FileNotFoundError:
    # doesn't exist
else:
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Python – How to copy a file in Python

shutil has many methods you can use. One of which is:

from shutil import copyfile
copyfile(src, dst)

# 2nd option
copy(src, dst)  # dst can be a folder; use copy2() to preserve timestamp

Copy the contents of the file named src to a file named dst. Both src and dst need to be the entire filename of the files, including path.
The destination location must be writable; otherwise, an IOError exception will be raised.
If dst already exists, it will be replaced.
Special files such as character or block devices and pipes cannot be copied with this function.
With copy, src and dst are path names given as strs.

Another shutil method to look at is shutil.copy2(). It's similar but preserves more metadata (e.g. time stamps).

If you use os.path operations, use copy rather than copyfile. copyfile will only accept strings.

Best Answer

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Python – How to copy a file in Python

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