如何验证 Powershell 的 .txt 文件中是否不存在字符串？

Question

I have 10.txt files and all these files have rows or records that start with 2-digit numbers like 01, 02, 03, 04... and so on.

File1.txt

01,333,abc,test2,44,55
02,883,def,test5,33,093
03....and so on.

1. Now, if powershell finds a file that doesn't contain a record that starts with either "01" or "02", then i want to throw an error or exception.

2. Also, if there is such kind of file, then i don't want to copy that invalid format file to the output folder. I only want to modify and copy txt files that have 01 or 02.

How can i do this?

    Get-ChildItem -Path 'C:\InputFiles\'-Filter '*.txt' -File | ForEach-Object { 
        $file = $_.FullName
        $FileData = Get-Content $file
    
        if($FileData[01] -notlike "01,"){
        Write-Host $file "File is INVALID"
    
        }

 $data = switch -Regex -File $file {
        '^01,' {
             do stuff...

        }

        '^02,' {
            
           do stuff...
        }
        
        default {$_}
    } 
   
    }

  $data | Set-Content -Path $file -Force 
        Copy-Item -Path $file -Destination 'C:\OutputFiles\' -Force
    
        
         

Answer 1

One way of doing this could be

Get-ChildItem -Path 'C:\InputFiles\'-Filter '*.txt' -File | ForEach-Object { 
    $isValid = $true
    switch -Regex -File $_.FullName {
        '^0[12],' { <# line begins with '01' or '02', so it's OK; do nothing #> }
        default   { $isValid = $false; break } 
    }
    if ($isValid) {
        # modify the file where you need and copy to the destination folder 
    }
    else {
        Write-Error "File $($_.FullName) is INVALID"
    }
}

or do it without using regex:

Get-ChildItem -Path 'C:\InputFiles\'-Filter '*.txt' -File | ForEach-Object { 
    $isValid = $true
    foreach ($line in (Get-Content -Path $_.FullName)) {
        if ($line -notlike '01,*' -and $line -notlike '02,*') {
            $isValid = $false 
            break
        }
    }   
    if ($isValid) {
        # modify the file where you need and copy to the destination folder 
    }
    else {
        Write-Error "File $($_.FullName) is INVALID"
    }
}