Thread: sending the output of one process, to the input of another

UPDATE: managaed to get this working thanks to a similar thread, and some adjustments here and there.


So far in my program i:

-Fork a new process

inside the child, i exec a program entered by the user.

I want to send the ouput of this program, down a pipe ( pipe 1 ), rather than to stdout.

I then want to exec another program, sending it the information in pipe 1, and then outputting to stdout.

Code:

pid = fork();
	if (pid == -1)
	  {
	    perror("dumbshell:fork");
	    exit(1);
	  }
	
	/* child */
	if (pid == 0)
	  {
	    /* dont need the read end */
	    close(fd[0]);
	    /* output will now be send down out pipe */
	    dup2(fd[1], STDOUT_FILENO);
	    
	    execvp(clist->exe_path,clist->arg);
	    fprintf(stderr,"No such command: %s\n",clist->exe_path);		
	    exit(1);
	    
	  }
	else
	  /* parent */	  
	  {

	    do
	      {
		npid = wait(&stat);
		//printf("Process %d exited with status %d\n",npid,stat);
	      }
	    while (npid != pid);

After the child exec's and exits, in the parent, i figure i create another child process, and exec in the newly created child.

How though, do i set it up so the new process reads from pipe 1, and outputs to stdout.

Hope I explained well enough for some to understand

Appreciate the help.

Code:

dup2(fd[1], STDOUT_FILENO);

You might want to see if that line is failing. I'm assuming you've already called pipe() and you've closed stdout.