sub Usage() {
  my $err = shift and select STDERR;
  print <<EOF;

------------------------------------------
-- Usage for the database backup script --
------------------------------------------

--host
      Specify the host IP

--engine
      Specify the database engine. This could be postgres or mysql.

--password
      Give the password needed to connect with the database server

--user
      Specify user to connect to the database server.
      The user must have permissions to connect to the database(s)

--port
      If another port than the standard must be used to connect you could
      specify this with the --port option

EOF
  exit $err;
}