my $array_ref = [
    "cn=a,dc=domain,dc=tld",
    "cn=b,dc=domain,dc=tld",
    "cn=c,dc=domain,dc=tld",
    "cn=d,dc=domain,dc=tld",
    "cn=e,dc=domain,dc=tld",
    "cn=f,dc=domain,dc=tld",
    "cn=g,dc=domain,dc=tld",
    "cn=h,dc=domain,dc=tld",
    "cn=i,dc=domain,dc=tld",
    "cn=j,dc=domain,dc=tld",
    "cn=k,dc=domain,dc=tld",
    "cn=m,dc=domain,dc=tld",
    "cn=n,dc=domain,dc=tld",
    "cn=o,dc=domain,dc=tld",
    "cn=l,dc=domain,dc=tld",
    ];

my @values = map { s/dc=domain,dc=tld/dc=sub,dc=otherdomain,dc=tld/i; $_ } @$array_ref;

print $_, "\n" for @values;