Punto 3

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>

#define READ 0
#define WRITE 1

int main(int argc, char *argv[]){
  if(strcmp(argv[3],"|") != 0 && strcmp(argv[3],">") != 0){
    char lim[] = " ";
    char *argsT[3];
    char *tok = strtok(argv[1],lim);
    int z=0;
    if(tok != NULL){
      while(tok != NULL){
      argsT[z]= tok;
      tok = strtok(NULL, lim);
      z++;
      }
    }
    argsT[2]=NULL;
    execvp(argsT[0], argsT);
  }//cierre de minishell con un comando

  else {//Inicia minishell si se paso pipe
    if(strcmp(argv[3],"|") == 0){
      pid_t pid;
      int  fd[2];
      char delimitador[] = " ";

      if (pipe(fd) == -1) {
        perror("Creating pipe");
        exit(EXIT_FAILURE);
      }

      switch(pid = fork()) {
     case 0:
        // The child process will execute wc.
        // Close the pipe write descriptor.
        close(fd[WRITE]);
        // Redirect STDIN to read from the pipe.
        dup2(fd[READ], STDIN_FILENO);
        //split the arguments of argv
        char *myargs2[3];
        char *token2 = strtok(argv[2], delimitador);
        int k=0;
        if(token2 != NULL){
          while(token2 != NULL){
            // Sólo en la primera pasamos la cadena; en las siguientes pasamos NULL
            myargs2[k]= token2;
            token2 = strtok(NULL, delimitador);
            k++;
         }
        }
myargs2[2]= NULL;
        // Execute wc -l
        execvp(myargs2[0],myargs2);

      case -1:
        perror("fork() failed)");
        exit(EXIT_FAILURE);

      default:
        // The parent process will execute ls.
        // Close the pipe read descriptor.
        close(fd[READ]);
        // Redirect STDOUT to write to the pipe.
        dup2(fd[WRITE], STDOUT_FILENO);
        //split the first string (command) to execute.
        char *myargs[3];
        char *token = strtok(argv[1], delimitador);
        int j=0;
        if(token != NULL){
          while(token != NULL){
            // Sólo en la primera pasamos la cadena; en las siguientes pasamos NULL
            myargs[j]= token;
            token = strtok(NULL, delimitador);
            j++;
         }
        }
        myargs[2]= NULL;
        //printf("%s" myar);
        // cat p4.c
        execvp(myargs[0], myargs);
      }
    }//cierra if del caso minishell pipe
    else{ if(strcmp(argv[3],">") == 0){

char limite[] = " ";
  char *argsU[3];
  char *toke = strtok(argv[1],limite);
  int x=0;
  if(toke != NULL){
    while(toke != NULL){
      argsU[x]= toke;
      toke = strtok(NULL, limite);
      x++;
    }
  }
  argsU[2]=NULL;
 int rc = fork();
    if (rc < 0) {
        // fork failed; exit
        fprintf(stderr, "fork failed\n");
        exit(1);
    } else if (rc == 0) {
        // child: redirect standard output to a file
        close(STDOUT_FILENO); 
        open(argv[2], O_CREAT|O_WRONLY|O_TRUNC, S_IRWXU);
        // now exec "comando"...
        execlp(strcat("./", argsU[0]), argsU[0], argsU[1], NULL); 
    } else {
        // parent goes down this path (original process)
        int wc = wait(NULL);
        assert(wc >= 0);
    }



}//cierra if caso redireccion minishell

    }
  }//cierra else despues del primer caso de minishell
return 0;
}//Cierre del main