int main(int argc, char *argv[]) {
    pid_t pid = fork();
    if(pid == 0) {
        setuid(123);
        seteuid(123);
        ptrace(PT_TRACE_ME, 0, NULL, 0);
        execl("/bin/ls", "/bin/ls", NULL);
    } else if(pid > 0) {
        int status;
        wait(&status);

        printf("Process %d started. Attach now, and click enter.n", pid);
        getchar();

        ptrace(PT_CONTINUE, pid, (caddr_t) 1, 0);
    }

    return 0;
}