how to Find string in txt file and delete line with this string

Question

I'd like to find a string COMMENT  in a txt file and can I delete this line . If you have any examples of

Vulpes · Answer

Try this code: using System; using System.IO; using System.Collections.Generic; class Test { static void Main() { string filePath = sasa.txt; string searchWord = COMMENT; string[] oldLines = File.ReadAllLines(filePath); List newLines = new List (); foreach(string line in oldLines) { if (!line.Contains(searchWord)) newLines.Add(line); } File.WriteAllLines(filePath newLines.ToArray()); } } You might want to use StartsWith() instead of Contains() and to do a case insensitive search by converting everything to (say) lower case.