If run without any redirection, we getCode:#include <iostream> using namespace std; int main ( ) { cout << "hello "; cerr << "this is an error"; // appears before hello if cout isn't flushed cout << "world" << endl; return 0; }
$ ./a.exe
this is an errorhello world
Redirecting stdout, we only see stderr on console
$ a.exe 1> f1.txt
this is an error
Redirecting stderr, we only see stdout on console
$ a.exe 2> f2.txt
hello world