$ perl -MModule::Build -e 'Module::Build->prompt("are you there","Y")'
are you there [Y] 
Y

##</code><code>##

  $user_install_base = Module::Build->prompt("Where to install?","/usr/local");
  Module::Build->new(
    ...
    install_base => $user_install_base,
    ...
  );

##</code><code>##

$ perl Build.PL install_base=/home/david

or

$ Build install install_base=/home/david