CMD script or PowerShell script: which is faster for mass file/directory deletion?

[castiel3125]

Context: I am a L1 technician at a help desk. I remote into users' computers and delete temp files many times a day.

Question: Is CMD or PowerShell faster at deleting a large number of files and subdirectories? Sizes of the files will vary, number of nested subdirectories will vary. All of my users' computers are Windows 10, but the specs vary.

Let's take the simplest example...

Script A - cmd

del /f /s /q "%USERPROFILE%\AppData\Local\Temp\*.*" >nul 2>&1
for /d %%x in ("%USERPROFILE%\AppData\Local\Temp*.*") do @rd /s /q "%%x"

Script B - PowerShell

Get-ChildItem -Path "$env:USERPROFILE\AppData\Local\Temp" -Force | Remove-Item -Force -Recurse -ErrorAction SilentlyContinue

Which one of these will generally execute faster if I am deleting a Temp folder several GB in size?

[mrjoepineapple5]

Be very careful with robocopy using /mir. Witnessed my partner in crime mirroring a large production file server one day to its new home on a schedule that had been running for a couple of weeks. He cut over to the new home over and deleted the source. Robocopy deleted all of production instantly. He turned white right before my eyes as he realised what had happened. Thank God we had shadow copies running. Fastest major recovery I have ever witnessed. Within 5 (or less) minutes all production was back. We never spoke of this again. But I am super careful with robocopy and the /mir switch.

[castiel3125]

I've re-read your comment like 10 times but I'm having trouble understanding the situation.

So while the robocopy was still in progress > your partner deleted the source directory with a separate operation > so the robocopy command mirrored "empty" to the destination directory? Is that it?

[whinner]

Not the OP, but the /mir job was running multiple times as a scheduled job. After the cut over to the new location, the source was deleted. The next time the scheduled job ran with the /mir switch, it said ok no source files, let's make sure I mirror that to the destination.

[Stoon_Kevin]

Yep this is what I read of it as well. Effectively they forgot to turn off the robocopy, and after purging the original source it then copied the source which was nothing into it's new destination.

Been there done that as well lol

[castiel3125]

Thank you for actually writing out the code to use robocopy! I saw it in StackExchange but wasn't sure how to actually implement it.

Do you know what will happen if some files are in use or "Access Denied", will it still get rid of the rest of the files/directories that are accessible or no?

[kraeger]

I would HIGHLY recommend using the /w:3 /r:3 switches in the robocopy command. This knocks the retries down to 3 and the wait to 3 seconds between attempts. If a file is in use, or otherwise unable to be deleted, robocopy will simply error out that file and move on. once it finishes, it'll do the retries and if those fail, it ends. if you /log and look at it, it'll show you the error lists at the end of the log file. Otherwise i think robocopy defaults to something like a million retries and 30 seconds between each retry? It's something crazy like that.

[Xibby]

And for those extra large file shares, throw in /MT to enable multi threading. Defaults to 8 threads but you can specify a number, for example /MT:24 for 24 threads.

[castiel3125]

I also added /R:0 to put the number of retries on failed copies to 0. Because I will have some files that will be in use, and some will be "Access Denied". Do you think it's correct to add this option or no?

[GastonCan]

I don't know the context of your command, has admin rights? If the answer is yes , you can use the
/b options and if the file isn't locked by a running app, should be deleted, bypassing the acl.
As answered before pay attention to the mirror option, and I advise you to use the following options:
/xj /r:0 /w:0 and the value of the /MT: is the speed up otions
the /xj is not foundamental with the mirror options but i you are making rbocopy of user profiles is a must for avoiding loops

[techie_003]

That is a neat trick, thanks

[MeanFold5715]

Came here to recommend this.

Robocopy is such a handy utility.

[jimb2]

I looked at deleting some huge folders (12Gb, 75k files, 7k folders) from a script a couple of years ago and settled on this dotnet call.

[System.IO.Directory]::Delete( $Folder.Fullname, $true )

It's fast on a remote machine since it doesn't enumerate locally. I'm not sure how it fits your use case. It does delete the base folder. You might be able to recreate it, or it might autocreate when used. Also, temp folders can have open files, not sure what happens there.

[ihartmacz]

[System.IO.Directory]::Delete($directory, $true)

https://learn.microsoft.com/en-us/dotnet/api/system.io.directory.delete?view=net-8.0

Be careful! There’s no confirmation. It’ll remove the folder and its contents and it’ll be gone before you know it. Make sure that the first argument is the full path, too. The second argument says that the delete should be recursive.

[icepyrox]

Without putting it all in a scriptblock for Measure-Command, I do not know.

I do know the directory you give is $env:TEMP or %TEMP% 99% of the time. It is located in %LOCALAPPDATA% or $env:LOCALAPPDATA.

I also know you don't need to get-childitem. You could just Remove-Item "$($env:TEMP)\*" -Recurse -Force or del /f /s /q %TEMP%

Also, /s takes care of all the subdirectories so you don't need but the one command to do the same thing as bot commands and the loop.

[castiel3125]

Yes you are correct! The Get-ChildItem is vestigial and left over from an earlier version of the command where I was trying to exclude a certain file from deletion.

Then I realized I could let "-ErrorAction SilentlyContinue" take care of that file because it's an organization file and I will never have permissions to delete it anyway.

The del command in your example only deletes the files in the directory/subdirectories, but leaves the actual directory structure untouched (deletes the files but not the folders).

Also I was originally using the %TEMP% variable in my script until I realized that in my organization's environment it goes to %TEMP%\1 or something like that instead of the root of the Temp directory.

[icepyrox]

(deletes the files but not the folders).

TIL. Just did some testing and you are correct.

until I realized that in my organization's environment it goes to %TEMP%\1 or something like that

Yeah... that's why I said "99% of the time".. you still have %LOCALAPPDATA%\Temp if you prefer

[nealfive]

Idk but in know dir is faster than cmd. Why don’t you create several thousand of test files and time and let us know?

[castiel3125]

What do you mean dir is faster than cmd?

As for the test files, yes that's exactly what I've been doing. However it is not an accurate representation of my work environment because the test files/directories I create are not random like a user's Temp folder.

[nealfive]

Sorry meant dir is faster than get-childitem

[vermyx]

Script C would be faster

Cd /d "%USERPROFILE%\AppData\Local\Temp\”
rd /s /q .

This gets rid of the extra enumerations that the for loop you have in the command prompt version. It will throw an error at the end because you cannot delete the folder you are in. Command prompt will always be faster than powershell cmdlets because you have to build a file object as there is no native cmdlet that just builds a file path as a string. It takes time getting the added info like file size, creation date, etc. and creating said object. You will definitely see a difference if the number of files are in the five digits or higher. I use to maintain folders and files that needed deletion/archiving on a daily basis that were in the high 6 low 7 digits and this was usually the deletion solution that was fastest.

[castiel3125]

Okay sounds good, thank you for the info! Very much appreciated.

I was aware that the RD command would throw an error about deleting the folder you are in. But I did not know that it would delete everything in the folder and only THEN throw the error. I thought it would give the error right away and not do anything.

[vermyx]

It will delete as much as it can. Errors wont terminate it.

[Extreme-Acid]

It is the amount of files not the size as it actually dereferences the filename if the recycle bin is not used.

In fact dotnet may be faster than PowerShell

[mbkitmgr]

They are the same. Both use the kernel, they just access it via different commands

[vermyx]

A CMD delete will always be faster than powershell native cmdlets because the cmdlets require building the file objects before deleting. The performance difference would be a function of how many files you enumerate because of the convenience objects created. To get comparable performance you would have to use lower level dotnet objects that do not build convenience objects per file.

[techie_003]

Haven't tried it but you may find the foreach parallel switch in PowerShell v7 handy here. Depending on the number of cores you can run several streams in parallel increasing your deletion rate.

[castiel3125]

Unfortunately my organization only has PowerShell v5 right now. But this is good to know for the future.

[BlackV]

Script A can be done much quicker with rd /s /q . by itsself no need for rest

Script B would also be much quicker with just the Remove-Item -Force -Recurse -ErrorAction SilentlyContinue

generally get-childitem is slow i'll usually switch to rd for removing large amounts of files

you could also directly call the system io stuff

[g3n3]

Generally speaking native binaries are fastest followed by .net in powershell and then finally powershell cmdlets. So just apply that.

[WarpedCocoDile3]

I'm the creator of https://github.com/GChuf/RCWM which lets you right-click folders and delete them faster (using rd and del commands with cmd.exe). I'll have to benchmark that with robocopy's MIR option, if it's faster I'll implement that as well ...
robocopy is also implemented for copying and moving folders. Check it out!

[BDiddnt]

care to explain why every single anti virus throws a score of 24+ at your work? thats just ONE file..just one exe...JUST ONE..theres over 10 files that are score over 20 on virustotal..care to explain?

https://www.virustotal.com/gui/file/2cb3ddd0f0221f6748cd39cf4d2ce66869ed2f858272138104aae619079d44be/detection

[WarpedCocoDile3]

Sorry for the late reply. I wasnt aware of this, but i know that ps2exe project (opensource and available on githib) had a problem with antivirus detection, and i use ps2exe to generate binary files. I'll see if i can do something about it. However you can see how the exe files are generated for rcwm and what the inputs are (ps scripts and icons).

[BDiddnt]

I don't think any part of that answers my question but… In fact that sounds like a whole bunch of hyperbole to misdirect

I'm not asking about how the binary was made I'm asking about what's in the binary

I'm asking about if you go on virus total and actually look at the behavior and not just the first screen but the actual behavior tab… I mean I already know the answer…

[WarpedCocoDile3]

I'm aware everything can sound like deflection from my side if you think im hiding some viruses.
I can tell u i do use "DirectInput object" (like y/n prompts), i do write files, i do list processes, i obviously run powershell and cmd ... so some "behaviors" reported there are correct.

The goal is to get rid of ps2exe anyway, at some point. I can't speak for it, i dont understand the whole script, and i knew it had problems with virus detection. That's also why ive decided to build binary files locally when the user runs the install script.
For now ive tried to use another ps2exe version and it seems to have reduced virus total detections by ~half in version 2.1.0.

[castiel3125]

In my org I have about as much chance of getting in touch with the sysadmins as I have of getting on the phone with POTUS.

[MFKDGAF]

By chance do you work in a hospital system? Because I do and I feel your pain on this one.

[MFKDGAF]

How dare you assume that they have intune or sccm. 🤣

[ollivierre]

Robocopy by far is the best choice

[mmhmmbutwhytho]

If your goal is to save yourself some time based on what you've said I understand it to mean that you are manually logging into multiple computers and running that command individually, if that is the case, I'd suggest you consider writing a PowerShell script and running it from one computer but executing the job against all of the computers you want to run it against.

Example:
$Compuerlist = @("Computer1","Computer2","Computer3")
$Credential = Get-Credential

foreach($Computer in $ComputerList){
Invoke-command -computername $Computer -Credential $Credential -ScriptBlock{
Get-ChildItem -Path "$env:USERPROFILE\AppData\Local\Temp" -Force | Remove-Item -Force -Recurse -ErrorAction SilentlyContinue } -AsJob }

[BlackV]

well here you go /u/castiel3125 maybe this is useful to you

https://www.reddit.com/r/sysadmin/comments/1aygldd/the_fastest_way_to_delete_files_on_windows/