How to write a regular expression in PowerShell - find specific string in filename and remove everything what comes after it

Question

I want to write a powershell script which should be able to remove searched string and everything after the searched string from a filename.

My code looks like this:

$path = "U:\PowerShell_Scripts\Test files"
$text1 = "_FULL.001_020_"
$text2 = "_HIGH.001_020_"
Get-ChildItem -Path $path -Filter "*$text1*" -Recurse |
    Rename-Item -NewName {$_.Name -replace $text1, ''}
Get-ChildItem -Path $path -Filter "*$text2*" -Recurse |
    Rename-Item -NewName {$_.Name -replace $text2, ''}

but it is not doing what I need of course. I have been looking the whole day via google, but this particular method is not possible to find, or I am using probably wrong search criteria.

Filenames which names should be manipulated:

SVT_ALL_HU__MGU_01__FULL.001_020_040.xml
SVT_ALL_HU__MGU_01__FULL.001_020_080.xml
SVT_ALL_HU__MGU_01__HIGH.001_020_249.xml

This is not a duplicate of "How to remove part of a string in powershell using Regular Expressions", because there is no multiple filename manipulation mentioned with starting fixed string.

Have you looked at PowerShell's own help on regex? Get-Help about_Regular_Expressions may be useful here - but remember that PowerShell is not a Linux shell, and requires a different mindset. — Jeff Zeitlin
– Jeff Zeitlin, Commented Aug 9, 2017 at 14:07
Possible duplicate of How to remove part of a string in powershell using Regular Expressions — cet51
– cet51, Commented Aug 9, 2017 at 14:08
Please read up on regular expressions and how they differ from globbing expressions. — Ansgar Wiechers
– Ansgar Wiechers, Commented Aug 9, 2017 at 14:13
Aside from the dot matching any character as a RegEx I don't see a problem with your code. Here the files got renamed to SVT_ALL_HU__MGU_01_040.xml SVT_ALL_HU__MGU_01_080.xml SVT_ALL_HU__MGU_01_249.xml in a test. So what's the problem? — user6811411
– user6811411, Commented Aug 9, 2017 at 18:02
The problem is the rest is still there in the filename. I want to find that specific string and then delete this string and everything what comes after that string. Beside that I need to make parallel process with same file, because the files are coming from developers with some funny stuff at start of filename (like: [{[]}]) which I need to delete manually and thats very annoying if I need to process over hundred files. Thatswhy I am asking for help, because I am not working with Regexp on everyday basis. — Pavol Durica
– Pavol Durica, Commented Aug 9, 2017 at 18:44

Maximilian Burszley · Accepted Answer · 2017-08-09 18:27:05Z

-2

This should do what you're requesting:

$path = "U:\PowerShell_Scripts\Test files"
$text1 = "_FULL.001_020_"
$text2 = "_HIGH.001_020_"
Get-ChildItem -Path $path -Filter "*$text1*" -Recurse |
  Rename-Item -NewName ($_.Name -replace '__F.*\.','.')
Get-ChildItem -Path $path -Filter "*$text2*" -Recurse |
  Rename-Item -NewName ($_.Name -replace '__H.*\.','.')

It will take SVT_ALL_HU__MGU_01__FULL.001_020_080.xml and make it SVT_ALL_HU__MGU_01.xml

edited Aug 9, 2017 at 18:27

answered Aug 9, 2017 at 14:25

Maximilian Burszley

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4 Comments

Pavol Durica Over a year ago

This is not working. I've tried it at home, even moved the directory outside from "C:\Users" to enhance naming compatibility to C:\Test\Files, but nothing happens with files when I run the code.

Maximilian Burszley Over a year ago

@PavolDurica Edited to remove script blocks. Those shouldn't be there.

Pavol Durica Over a year ago

Rename-Item : Cannot bind argument to parameter 'NewName' because it is an empty string. At C:\Test\File_rename2.ps1:4 char:78 + ... t1*" -Recurse | Rename-Item -NewName ($_.Name -replace '__F.*\.','.') + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : InvalidData: (:) [Rename-Item], ParameterBindingValidationExcept ion + FullyQualifiedErrorId : ParameterArgumentValidationErrorEmptyStringNotAllowed,Microsoft. PowerShell.Commands.RenameItemCommand

Ansgar Wiechers Over a year ago

You MUST use scriptblocks there. Parentheses won't work, because with them PowerShell won't defer the expansion of $_ (i.e. $_ is expanded when the Get-ChildItem ... | Rename-Item ... statement is parsed rather than when Rename-Item is invoked).

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