Merge branch '679-opal-header-is-not-printed-in-interactive-mode' into 'OPAL-2021.1'

Resolve "OPAL header is not printed in interactive mode"

See merge request !534

(cherry picked from commit d2009a3b)

20db1d03 Print OPAL header in interactice mode

src/Main.cpp

@@ -215,6 +215,7 @@ int main(int argc, char *argv[]) {
         }
 
         if(argc <= 1) {
+            ::printStdoutHeader();
             // Run commands from standard input
             parser.run(new TerminalStream("OPAL"));
         } else {