CODEWITHSUNDEEP
powershell
Niner
Niner

Reputation: 2205

find and delete lines without string pattern in text files

I'm trying to find out how to use powershell to find and delete lines without certain string pattern in a set of files. For example, I have the following text file:

111111
22x222
333333
44x444

This needs to be turned into:

22x222
44x444

given that the string pattern of 'x' is not in any of the other lines.

How can I issue such a command in powershell to process a bunch of text files?

thanks.

Upvotes: 2

Views: 2323

Answers (2)

Shay Levy
Shay Levy

Reputation: 126762

This will process all txt files from the working directory. Each file content is checked and only lines that have 'x' in them are allowed to pass on. The result is written back to the file.

Get-ChildItem *.txt | ForEach-Object{
    $content = Get-Content $_.FullName | Where-Object {$_ -match 'x'}
    $content | Out-File $_.FullName
}

Upvotes: 2

Todd Li
Todd Li

Reputation: 3269

dir | foreach { $out = cat $_ | select-string x; $out | set-content $_  }

The dir command lists the files in the current directory; the foreach goes through each file; cat reads the file and pipes into select-string; select-string finds the lines that contains the specific pattern, which in this case is "x"; the result of select-string is stored in $out; and finally, $out is written to the same file with set-content.

We need the temporary variable $out because you cannot read and write the same file at the same time.

Upvotes: 3

Related Questions