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

int main(int argc, char * argv[]){
 int fdin = open("a2b", O_RDONLY);
 int fdout = open("b2a", O_WRONLY);

 char buf[1024];
 for (;;) {
	 ssize_t n;
	 write (STDOUT_FILENO, "> ", 2);
	 n = read(fdin, buf, 1024);
	 write (STDOUT_FILENO, buf, n);
	 n = read(STDIN_FILENO, buf, 1024);
	 write (fdout, buf, n);
 }
}