Remove lines from a text file if it contains a string

Suppose you want to write that in the same file, you can do as follows:

Set-Content -Path "C:\temp\Newtext.txt" -Value (get-content -Path "c:\Temp\Newtext.txt" | Select-String -Pattern 'H\|159' -NotMatch)

You don't need Select-String in this case, just filter the lines out with Where-Object

Get-Content C:\new\temp_*.txt |
    Where-Object { -not $_.Contains('H|159') } |
    Set-Content C:\new\newfile.txt

String.Contains does a string comparison instead of a regex so you don't need to escape the pipe character, and it's also faster

Another option for writing to the same file, building on the existing answers. Just add brackets to complete the action before the content is sent to the file.

(get-content c:\new\sameFile.txt | select-string -pattern 'H`|159' -notmatch) | Set-Content c:\new\sameFile.txt

The pipe character | has a special meaning in regular expressions. a|b means "match either a or b". If you want to match a literal | character, you need to escape it:

... | Select-String -Pattern 'H\|159' -NotMatch | ...

This is probably a long way around a simple problem, it does allow me to remove lines containing a number of matches. I did not have a partial match that could be used, and needed it to be done on over 1000 files. This post did help me get to where I needed to, thank you.

$ParentPath = "C:\temp\test"
$Files = Get-ChildItem -Path $ParentPath -Recurse -Include *.txt
$Match1 = "matchtext1"
$Match2 = "matchtext2"
$Match3 = "matchtext3"
$Match4 = "matchtext4"
$Match5 = "matchtext5"
$Match6 = "matchtext6"
$Match7 = "matchtext7"
$Match8 = "matchtext8"
$Match9 = "matchtext9"
$Match10 = "matchtext10"

foreach ($File in $Files) {
    $FullPath = $File | % { $_.FullName }
    $OldContent = Get-Content $FullPath
    $NewContent = $OldContent `
    | Where-Object {$_ -notmatch $Match1} `
    | Where-Object {$_ -notmatch $Match2} `
    | Where-Object {$_ -notmatch $Match3} `
    | Where-Object {$_ -notmatch $Match4} `
    | Where-Object {$_ -notmatch $Match5} `
    | Where-Object {$_ -notmatch $Match6} `
    | Where-Object {$_ -notmatch $Match7} `
    | Where-Object {$_ -notmatch $Match8} `
    | Where-Object {$_ -notmatch $Match9} `
    | Where-Object {$_ -notmatch $Match10}
    Set-Content -Path $FullPath -Value $NewContent
    Write-Output $File
}

If you anyone having this issue while doing what suggested by Robert Brooker-

*These files have different encodings. Left file: Unicode (UTF-8) with signature. Right file: Unicode (UTF-8) without signature. You can resolve the difference by saving the right file with the encoding Unicode (UTF-8) with signature.* with Set-Content

use -Encoding UTF8

so like this

(get-content c:\new\sameFile.txt | select-string -pattern 'H`|159' -notmatch) | Set-Content c:\new\sameFile.txt -Encoding UTF8

I would personally prefer ForEach-Object for faster operation, Since it avoids the use of Select-String

$inputFile = "C:\new\temp_*.txt"
$outputFile = "C:\new\newfile.txt"

Get-Content $inputFile | ForEach-Object {
 if ($_ -notmatch "H\|159") {
    $_
  }
} | Set-Content $outputFile