use strict;

my $x = "august ferdinand mobius";
my $y = replace($x, '\b(\w)', '\U$1', 'igs');
print $y;

sub replace {
    my($text, $pattern, $replacement, $modifiers) = @_;
    my $result = '';
    eval '($result = $text)'."=~ s/$pattern/$replacement/$modifiers";
    return $result;
}