For instance, instead of: $ ./frysk/bindir/ftrace -- ./frysk/pkglibdir/funit-fib-fork 3 10409.10409 attached [...]/funit-fib-fork fib (3) = 2 10409.10409 exited with status 0 default to: $ ./frysk/bindir/ftrace -- ./frysk/pkglibdir/funit-fib-fork 3 10472.10472 attached [...]/funit-fib-fork 10473.10473 attached [...]/funit-fib-fork 10475.10475 attached [...]/funit-fib-fork 10474.10474 attached [...]/funit-fib-fork 10476.10476 attached [...]/funit-fib-fork 10475.10475 exited with status 1 10474.10474 exited with status 1 10476.10476 exited with status 0 10473.10473 exited with status 1 fib (3) = 2 10472.10472 exited with status 0 with options to both explicitly enable / disable the behavior.