>perl -wMstrict -le
"my $orig = 'fEEfoobarFIEFOOBARFoEfOoBaRfUM';
 my $mod  = 'Foo-Bar';
 ;;
 (my $modmod = $mod) =~ tr/-//d;
 my $new = join $mod, map lc(), split /\Q$modmod\E/i, $orig, -1;
 print qq{'$new'};
"
'feeFoo-BarfieFoo-BarfoeFoo-Barfum'