#include<unistd.h>
#include<stdio.h>

int main(){

	// make a pipe
	int pipe_fds[2]; // read end is pipe_fds[0], write end is pipe_fds[1]
	pipe(pipe_fds); 

	char *cmd1 = "who";
	char *cmd2 = "sed";
  	char *cmd2_argument = "s/i/A/g";
	// Run cmd1 | cmd2, in this case:  who | sed s/i/A/g
	
	pid_t pid = fork();
	if(pid){ // We're the parent
		dup2(pipe_fds[1], 1);	
		execlp(cmd1, cmd1, 0);
		perror("running who");

	} else { // We're the child
		dup2(pipe_fds[0], 0);
		execlp(cmd2, cmd2, cmd2_argument, 0);
	}

	// This won't print
	puts("Reached the end of the program\n"); 
	return 0;
}