my @output= map{ $data=~s/C_USERNAME/$_/rg} @arr;
my @output1= map{ $data=~s/IP/$_/rg} @arr1; 

##</code><code>##

my @usernames = map { $data =~ s/C_USERNAME/$_/rg } @arr;

my @user_and_ip;
for my $user_string (@usernames) {
    push @user_and_ip, map { $user_string =~ s/IP/$_/rg } @arr1;
}