use strict;
use warnings;
use Data::Dumper;

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

for (@$AoH_orig) {$_->{'title'} =~ s/-/_/g};

print Dumper($AoH_orig);