Renaming of files and content within files using Powershell

Question

Can somebody please support for renaming of files and content within files using Powershell:

• Root folder contains files (xml, txt and others), also subfolders are contained that themselves contain files
• All occurrences of a certain wording in all contained files in all subfolders should be renamed
• Additional requirements:
  • "abc" in the example may also be in capital letters or even mixed (e.g. "ABC", "Abc")
  • Additionally, the file name shall be renamed. This works: ls | Rename-Item -NewName {$_ -replace 'uvw', 'xyz' }. What needs to be added to also cover capital and/or mixed letters? And how to include this in the script below to rename all files in all subfolders in one go?

Tried a bit around including other parameters on the basis of other posts on the topic here but stumbled on access denied issues and others. It only worked - excluding the extra requirements mentioned - when providing the individual subfolders for $filePath using the following script. Please advice for making it work for the requirements mentioned:

$filePath = "C:\root_folder"
Get-ChildItem $filePath -Recurse | ForEach {
     (Get-Content $_ | ForEach  { $_ -creplace 'abc_123', 'def_123' }) |
     Set-Content $_
}

Answer 1

• PowerShell operators that support string operations are case-insensitive by default, including -replace, so no extra effort is needed for case-insensitive matching: 'uVw' -match 'uvw' is $true, for example.

  • You would only use the -creplace variant if you explicitly want case-sensitivity (the c prefix, which can also applied to other operators such as -match (-cmatch) and -eq (-ceq), indicates case-sensitivity).

• If you want to process only files in a recursive Get-ChildItem call, add the -File switch.

  • By default, directories are included in the enumeration, and attempting a Get-Content call on a directory results in an 'Access denied' error in Windows PowerShell (the error message has since been improved in PowerShell (Core) 7+).

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Therefore, you're probably looking for something like the following:

• Caveats:

  • In your attempt you process all files in your directory tree; while trying to rename files to their existing name is a benign no-op (if the string to replace isn't found), unconditionally rewriting the content of files based on a -replace operation will corrupt non-text files, and with text files can change their character encoding.

  • Therefore, it's best to:

    • Limit processing to file types of interest, as indicated by their extensions, by adding, e.g., -Include *.txt, *.xml to the Get-ChildItem call, as shown below.
    • Use an explicit -Encoding argument to control the output character encoding.
    • Additionally, you may want to rewrite the files only if an actual string replacement was performed.

  • While the -replace operations match case-insensitively, the replacement strings are used as-is; e.g. '-ABC-' -replace 'abc', 'def' results in '-def-'.

    • Your follow-up question is about also case-matching the replacement text based on the matched text, so that the result in the above example would be '-DEF-'

$filePath = "C:\root_folder"
$include = '*.txt', '*.xml' # adapt as needed
Get-ChildItem -File $filePath -Recurse -Include $include | 
  Rename-Item -WhatIf -PassThru -NewName { $_.Name -replace 'uvw', 'xyz' } |
  ForEach-Object {
     # NOTE: You may have to use an -Encoding argument here to ensure
     #       the desired character encoding.
     ($_ | Get-Content -Raw) -replace 'abc_123', 'def_123' |
       Set-Content -NoNewLine -LiteralPath $_.FullName
  }

^{Note: The -WhatIf common parameter in the command above previews the operation. Remove -WhatIf and re-execute once you're sure the operation will do what you want.}