Change content of a file based on a content of another file

Question

I have this file structure

In PowerShell my location is set to Folder. SubSubFolders has a lot of xml files, and I want to add a line there only if content of version.txt file is a and that line doesn't exist there already.

I was able to figure out how to change an xml file in particular SubSubFolder, but I can't do it when I start in Folder folder and and taking into consideration version

#here I need to add: only if version.txt content of xml file in parent folder is "a"
$files = Get-ChildItem -Filter *blah.xml -Recurse | Where{!(Select-String -SimpleMatch "AdditionalLine" -Path $_.fullname -Quiet)} | Format-Table FullName

foreach($file in $files)
{
    (Get-Content $file.FullName | Foreach-Object {  $_
                                                if ($_ -match "AdditionalLineAfterThisLine")
                                                {
                                                    "AdditionalLine"
                                                }
    }) | Set-Content $file.FullName
}

As an aside: `Format-*` cmdlets output objects whose sole purpose is to provide _formatting instructions_ to PowerShell's output-formatting system - see [this answer](https://stackoverflow.com/a/55174715/45375). In short: only ever use `Format-*` cmdlets to format data _for display_, never for subsequent _programmatic processing_. — mklement0, Dec 01 '21 at 22:46

mklement0 · Accepted Answer · 2021-12-01T23:45:45.720

2

If I understand you correctly, you're looking for the following:

$files = (
  Get-ChildItem -Filter *blah.xml -Recurse | 
    Where-Object{
      -not ($_ | Select-String -SimpleMatch "AdditionalLine" -Quiet) -and
      (Get-Content -LiteralPath "$($_.DirectoryName)/../version.txt") -eq 'a'
    }
).FullName

Note that the assumption is that the version.txt file contains just one line. If it contains multiple lines, the -eq 'a' operation would act as a filter and return all lines whose content is 'a', which in the implied Boolean context of -and would yield $true if one or more such lines, potentially among others, exist.

edited Dec 01 '21 at 23:45

answered Dec 01 '21 at 22:45

mklement0

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@EricKlaus, my bad: please see my update. (The negation must indeed be applied to the `Select-String` call as a whole, as in your original approach; combining `-NotMatch` with `-Quiet` doesn't work as I expected.) – mklement0 Dec 01 '21 at 23:47

Change content of a file based on a content of another file

1 Answers1