How Do I Read And Process Big Log File In C#

string path = @"C:\Somewhere\SomeLogFile.log";
string line;

using (StreamReader sr = File.OpenText(path)) {
   while ((line = sr.ReadLine()) != null)) {
      // Do whatever you have to do with line variable 
   }
}

sing System;
using System.IO;
using System.Threading.Tasks;

namespace LogfileParser
{
    class Program
    {
        static void Main(string[] args)
        {
            // Prompt the user to enter the search string
            Console.Write("Enter search string: ");
            string searchString = Console.ReadLine();

            // Open the logfile using a FileStream
            using (FileStream stream = new FileStream("logfile.txt", FileMode.Open, FileAccess.Read))
            {
                // Initialize the counter for the number of occurrences
                int count = 0;

                // Read the logfile in blocks of 4096 bytes
                byte[] buffer = new byte[4096];
                int bytesRead;
                while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) > 0)
                {
                    // Use Parallel.ForEach to search for the search string in multiple threads
                    Parallel.ForEach(buffer.Split('\n'), line =>
                    {
                        // Check if the line contains the search string
                        if (line.Contains(searchString))
                        {
                            // Increment the counter if the search string is found
                            Interlocked.Increment(ref count);
                        }
                    });
                }

                // Print the result to the user
                Console.WriteLine($"Found {count} occurrences of '{searchString}' in the logfile.");
            }
        }
    }
}