Не проходит валидацию, но на своих файлах все работает.
package com.javarush.task.task18.task1827;
/*
Прайсы
*/
import java.io.*;
public class Solution {
public static void main(String[] args) throws Exception {
String fileName;
try(BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in))){
fileName=bufferedReader.readLine();
}
if(args.length != 0&&args[0].contains("c")){
try(BufferedReader bufferedReader1= new BufferedReader(new FileReader(fileName));
BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(fileName, true))){
int count=0;
int buf=0;
String sb;
while ((sb=bufferedReader1.readLine())!=null){
buf=Integer.parseInt(sb.substring(0,8).trim());
if(count<buf) count=buf;
}
bufferedWriter.write(String.format("%-8d%-30s%-8s%-4s",count++,args[1],args[2],args[3]));
}
}
}
}