Depending on SSH client configuration and HP-UX release it is possible that the backspace control key (which is used for deleting erroneous inputs) is not working as expected.
# mn^?^?man mn^?^?man: command not found
A possibility is to modify the configuraton of PuTTy – but this requires resetting the current session.
Alternatively the stty command can be used with the following parameters to re-define the backspace control key:
# stty erase ^? #
And now, deleting erroneous inputs is working again. 😉