I was debugging (or being humble, trying to seek understanding through following the works left by more experienced people) and when the perl debugger reach the statement

                  ($pid = fork) or last;
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the console showed the message:

######### Forked, but do not know how to change a TTY. #########
  Define $DB::fork_TTY
       - or a function DB::get_fork_TTY() which will set $DB::fork_TTY
+.
  The value of $DB::fork_TTY should be the name of TTY to use.
  On UNIX-like systems one can get the name of a TTY for the given
   window by typing tty, and disconnect the shell from TTY by
   sleep 1000000.
  DB<4>   DB<4>
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And I found myself lost, because I don't know how to "follow" the child process, nor why the terminal seems so weird, "swallowing" every other char that I type in it.

I don't know if matters, but I am using the PuTTY terminal, through a SSH connection.

So, could anyone help me:
- how do I this mess (the terminal input/output) in right order,
- and continue the debugging, following the child process?

Thanks for all concerns.