#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <getopt.h>
int
cat(int fd,const char *filename)
{
  int c;
  char buf[8192];

  if(fd != 0)
    fd = open(filename, O_RDONLY);

  if (fd == -1)
    {
      fprintf(stderr,"Error opening file\n");
      return 1;
    }

  while((c = read(fd,buf,sizeof(buf))) > 0)
    write(1,buf,c);
  close(fd);
  return 0;
}
int
main(int argc, char *argv[])
{

  if(argc == 1)
    cat(0,NULL);
  else
    for(int i = optind; i<argc;i++)
      {
	int c = getopt(argc, argv, "u");
	cat(1,argv[i]);
      }

  return 0;
}