Test task

Test task

using System;
using System.IO;
using System.Linq;

namespace TestApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            if (!args.Any())
            {
                Console.WriteLine("Error! Invalid command argument");
                Console.ReadKey();
            }
            else
            {
                var filePath = args.First();
                if (!File.Exists(filePath))
                {
                    Console.WriteLine("Error! File does not exist!");
                    Console.ReadKey();
                }
                else
                {
                    var allWords = File.ReadAllText(filePath)
                        .Split(new[] { '.', '?', '!', ' ', ';', ':', ',' }, StringSplitOptions.RemoveEmptyEntries);
                    if (!allWords.Any())
                    {
                        Console.WriteLine("Error! File does not contains words!");
                        Console.ReadKey();
                    }
                    else
                    {
                        foreach (var x in allWords.Distinct(StringComparer.CurrentCultureIgnoreCase).Select(word => new
                        {
                            Word = word.ToLower(),
                            Count = allWords.Count(w => w.Equals(word,StringComparison.CurrentCultureIgnoreCase))
                        }).OrderByDescending(w => w.Count).ThenBy(w=>w.Word).Take(20))
                        {
                            Console.WriteLine("{0} {1}", x.Word, x.Count);
                        }
                        Console.ReadKey();
                    }
                    
                }
            }
        }
    }
}