#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#define FFLAG (O_WRONLY | O_CREAT | O_TRUNC)
#define FMODE (S_IRUSR | S_IWUSR)

int parseandredirectin(char *cmd) {    /* redirect standard input if '<' */
   int error;
   int infd;
   char *infile;

   if ((infile = strchr(cmd, '<')) == NULL)
      return 0;
   *infile = 0;                  /* take everything after '<' out of cmd */
   infile = strtok(infile + 1, " \t");
   if (infile == NULL)
      return 0;
   if ((infd = open(infile, O_RDONLY)) == -1)
      return -1;
   if (dup2(infd, STDIN_FILENO) == -1) {
      error = errno;                       /* make sure errno is correct */
      close(infd);
      errno = error;
      return -1;
   }
   return close(infd);
}

int parseandredirectout(char *cmd) {  /* redirect standard output if '>' */
   int error;
   int outfd;
   char *outfile;

   if ((outfile = strchr(cmd, '>')) == NULL)
      return 0;
   *outfile = 0;                  /* take everything after '>' out of cmd */
   outfile = strtok(outfile + 1, " \t");  
   if (outfile == NULL)
      return 0;
   if ((outfd = open(outfile, FFLAG, FMODE)) == -1)
      return -1;
   if (dup2(outfd, STDOUT_FILENO) == -1) {
      error = errno;                        /* make sure errno is correct */
      close(outfd);
      errno = error;
      return -1;
   }
   return close(outfd);
}