Tiny stand-alone flat file sampling utility.

FlatSampling.cs

using System;
using System.IO;
using System.IO.Compression;
using System.Text;

namespace Loader
{
    class FlatSampling
    {
        static void Main(string[] args)
        {
            if (args.Length != 2)
            {
                Console.WriteLine(
@"Flat file sampling utility. 

Usage
    flatsamping.exe filename samplerate

Where:
    'filename' is the target file
    'samplerate' is an integer representing sampling rate

");
                return;
            }

            string source = args[0];
            var rate = int.Parse(args[1]);

            if (source.EndsWith(".gz"))
            {
                using (var file = new FileStream(source, FileMode.Open))
                using (var zip = new GZipStream(file, CompressionMode.Decompress))
                using (var reader = new StreamReader(zip, Encoding.UTF8))
                {
                    Read(reader, rate);
                }
            }
            else
            {
                using (var file = new FileStream(source, FileMode.Open))
                using (var reader = new StreamReader(file, Encoding.UTF8))
                {
                    Read(reader, rate);
                }
            }
        }

        private static void Read(StreamReader reader, int rate)
        {
            int lineIndex = 0;
            string line = null;

            while ((line = reader.ReadLine()) != null)
            {
                if(lineIndex++ % rate == 0) Console.WriteLine(line);   
            }
        }
    }
}