#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <fcntl.h>
    
    int main(int argc, char *argv[])
    {
      int in;
      int out;
      size_t got;
      char buffer[1024];

      in = open (argv[1], O_RDONLY);
      out = open (argv[2], O_TRUNC | O_CREAT | O_WRONLY, 0644);

      if ((in <= 0) || (out <= 0))
      {
        fprintf (stderr, "Couldn't open a file\n");
        exit (errno);
      }
      
      dup2 (in, 0);
      dup2 (out, 1);
      
      close (in);
      close (out);

      while (1)
      {
        got = fread (buffer, 1, 1024, stdin);  
        if (got <=0) break;
        fwrite (buffer, got, 1, stdout);
      }
    }