UNIX for Advanced & Expert Users

	int pipeID[2]; /* Pipes Have two values, one for the process A */
                                /* And one for process B. Think of each value */
                                /* as an end to the pipe */
/* pipeid[0] is process A, pipeid[1] is process B */
	pipe(pipeID); /* Create Pipe. */
	
    /* Fork current process to create process A and process B. */
/*Both child processes. Process A is created by the first fork(), */
/*process B by the second fork().  */

// Process A code
	if (fork()==0){ /* If the new process A is a child */
	    // child
		close(pipeID[0]);         //write stdout
		dup2(pipeID[1],1);       // to pipe using dup
		fillArgs(sPipe[0],&args); /* Create agrc and argv */
		execvp(args.argv[0],args.argv); // Execute
		close(pipeID[1]);// stdout goes to pipe.
	}
// Process B code
	if (fork()==0){ /* If the new process is a child */
		close(pipeID[1]);		//read from pipe 1 stdout
		dup2(pipeID[0],0);		//as stdin.
		fillArgs(sPipe[1],&args2);   /* Create argc and argv */
		execvp(args2.argv[0],args2.argv); // Execute 
		close(pipeID[0]);// process B reads stdin from pipe
	}
	close(pipeID[1]); /* Close pipes else, we don't want to have stdin, and stdout */	
	close(pipeID[0]); /* permanently redirected. */