//To create and write text to a file:
import java.lang.*;
import java.io.*;
 
public class Create
{
    String command="";
    BufferedReader br;
    BufferedWriter out;
    File file = new File("f1");
 
    public void createFile()
    {
        try {
            //File file = new File("f1");
 
            // Create file if it does not exist
            boolean success = file.createNewFile();
            if (success)
            {
            writeFile();
            }
            else
            {
                 System.out.println("file already exists");
 
            }
        } catch (IOException e) {}
    }
 
 
    public void writeFile()
    {
        try {
 
            out = new BufferedWriter(new FileWriter(file));
            out.write("You have passed  \n");
            out.write("The Exams");
            out.close();
        } catch (IOException e) {}
    }
 
}

//To read file
import java.lang.*;
import java.io.*;
 
public class Read
{
    BufferedReader br;
    BufferedWriter out;
    public void readFile()
    {
        try {
            br = new BufferedReader(new FileReader("f1"));
            String Str;
            while ((Str = br.readLine()) != null)
            {
                   System.out.println(Str);
            }
            br.close();
 
        } catch (IOException e) {}
    }
}

//To copy file
import java.lang.*;
import java.io.*;
 
public class Copy
{
    public void copyFile()
    {
        try{
            InputStream in = new FileInputStream("f1");
            OutputStream out = new FileOutputStream("f2");
 
            // Transfer bytes from in to out
            byte[] buf = new byte[1024];
            int length;
            while ((length = in.read(buf)) > 0)
            {
                out.write(buf, 0, length);
            }
            in.close();
            out.close();
            System.out.println("File copied.");
        }catch(IOException e) {}
    }
}

 
//To remove file
import java.lang.*;
import java.io.*;
 
public class Remove
{
    public void removeFile(File file)
    {
        boolean success = file.delete();
        if (!success)
        {
            System.out.println("File not deleted");
        }
    }
}

//To check for substring
 
import java.lang.*;
import java.io.*;
 
public class Sub
{
 
    BufferedReader br;
    BufferedWriter out;
 
    public void Search()
    {
        try {
            br = new BufferedReader(new FileReader("f1"));
            String Str;
            while ((Str = br.readLine()) != null)
            {
                   System.out.println(Str);
 
                   boolean found = true;
 
                   int index = Str.indexOf("have");
                   if(found)
                   {
 
                    System.out.println("Substring found");
                    System.out.println(br.readLine());
                }
                else
                    System.out.println(" ");
            }
            br.close();
 
        } catch (IOException e) {}
    }
 
 
}