#I get this
my @array = qw(aaa-aaa bbb-bbb ccc-ccc);
my @newarray = map { $_ =~ s/-/_/g } @array;
print Dumper(@array);

my $AoH_orig = [ { 'title' => 'aaa-aaa',
                   'name'  => 'tom' },
                 { 'title' => 'bbb-bbb',
                   'name'  => 'kathy' },
                 { 'title' => 'ccc-ccc',
                   'name'  => 'bill' } 
                 ];

# how i would do it "long hand"            
for ( 0 .. $#$AoH_orig ) {
	$AoH_orig->[$_]{'title'} =~ s/-/_/g;
}

#try mapping
my $AoH_new = map { $AoH_orig->[$_]{'title'} =~ s/-/_/g } @$AoH_orig;
 #or 
my $AoH_new = map { $_->{'title'} =~ s/-/_/g } @$AoH_orig; 
 
print Dumper($AoH_orig);