gistfile1.txt

kim-jong-deux :: ~ % cat hello.cpp                                                                                                                                                                                                                                              
#include <iostream>
#include <unistd.h>

int main() {
    std::cout << isatty(0) << '\n';
    std::cout << isatty(1) << '\n';
    std::cout << isatty(2) << '\n';
}
kim-jong-deux :: ~ % ./a.out                                                                                                                                                                                                                                                    
1
1
1
kim-jong-deux :: ~ % ./a.out | cat                                                                                                                                                                                                                                              
1
0
1