PowerShell: How do I append a prefix to all files in a directory?

Question

Currently I'm using cmdlets like:

dir | rename-item -NewName {$_.name -replace "-","_"}

But now I need to add a prefix to the filename for all files in the directory.
I can't predict how long each filename is (it varies), so I can't just use a bunch of . wildcards.

I need it to append a fixed phrase to the beginning of each filename, regardless what that filename is.

See solution here http://stackoverflow.com/a/20874916/5518385 — Yisroel Tech, May 07 '17 at 22:53
What is it now? A prefix or a suffix? For a prefix you already got a name so (literally) just add to your prefix or (for a suffix) just add the suffix to it. — Seth, May 08 '17 at 12:09

score 29 · Accepted Answer · edited Jan 29 '21 at 02:57

29

An alternative approach to a regular expression would be to use simple string operations to create the new file name.

$items=Get-ChildItem;
$items | Rename-Item -NewName { "Prefix_" + $_.Name };

edited Jan 29 '21 at 02:57

Blaze

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answered May 08 '17 at 12:12

Seth

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I'm trying this, but it seems to go mad and keep trying to prefix filenames over and over until it crashes from the filename being too long - e.g. running the command above results in filenames like `Prefix_Prefix_Prefix_Prefix_Prefix_Prefix_Prefix_Prefix_Prefix_Prefix_...` – Tom Carpenter Sep 02 '17 at 14:37
Split the command. `$items = Get-ChildItem;` And replace the `Get-ChildItem` in the above case with `$items`. – Seth Sep 06 '17 at 10:21
2

In the end based on [this](https://stackoverflow.com/a/37279979/1557472), I just added ```-Exclude Prefix_*``` to the `Get-ChildItem` command. – Tom Carpenter Sep 06 '17 at 10:23
Make it into a one liner without the variables: ``Get-ChildItem C:\Directory\Path -File | Rename-Item -NewName { "PrefixName_" + $_.Name }`` – DBADon Dec 01 '22 at 19:25

LotPings · Answer 2 · 2019-04-25T16:27:25.430

13

You are quite near.

-replace uses RegEX and in a Regular Expression you anchor at the beginning with a ^
for a suffix you can similarly replace the anchor at line end with $
to avoid any possible re-iteration of the renamed file enclose the first element of the pipeline in parentheses.

(Get-ChildItem -File) | Rename-Item -NewName {$_.Name -replace "^","Prefix_"}

edited Apr 25 '19 at 16:27

answered May 08 '17 at 11:38

LotPings

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I like this answer because it doesn't cause an infinite loop and I don't need to write the prefix twice - like what happens in other solutions with the `-Exclude Prefix_*` to avoid the loop. – TCB13 Jul 16 '18 at 07:34

score 1 · Answer 3 · edited May 25 '20 at 01:16

1

To remove prefix of all in folder:

Get-ChildItem 'Folderpath\KB*' | Rename-Item -NewName { $_.Name -replace 'KB*','' }

To Add a prefix to all in folder:

foreach($item in 'Folderpath')
{
Get-ChildItem 'C:\Users\ilike\OneDrive\Desktop\All in one script\Single Patch here' | Rename-Item -NewName { "KB" + $_.Name }
}

Took a while, hope this can help others in need

edited May 25 '20 at 01:16

Reddy Lutonadio

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answered May 24 '20 at 08:38

donovan dunaway

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score 0 · Answer 4 · answered Oct 25 '20 at 00:02

get-childitem *.FileExtension_ | foreach { rename-item $_ $.Name.Replace($.Name,"Prefix_" + $_.Name) }

Replace FileExtension_ with the extension corresponding to the filetype you want to add prefix to. Or just remove .FileExtension_ along with the "." to add prefix to all files in working directory. Replace Prefix_ with the desired prefix.

PowerShell: How do I append a prefix to all files in a directory?

4 Answers4