This is in particular helpful if the script is run as background process and would never work
again without manual intervention, for example at
[ -z "$LKD" ] && \
err '' "cannot use queue $MSMTPQ_Q : waited $MAX seconds for"\
" lockdir [ $LOK ] to vanish ; giving up"\
'if you are certain that no other instance of this script'\
" is running, then 'rmdir' the lock dir manually" '' # lock file still there, give up
This is in particular helpful if the script is run as background process and would never work again without manual intervention, for example at