use warnings;
use strict;
use Data::Dumper qw(Dumper);

my $clk_new;
my @clk_new;

my @clk =  ('ux_prim_clk', 'ux_side_clk', 'ux_xtal_frm_refclk');

my @clk_output = map [ split /_/, $_ ], @clk;

print Dumper \@clk_output;

for ( my $c= 0; $c<= $#clk_output; $c++) {
   for ( my $d = 0; $d <= $#{$clk_output[$c]}; $d++ ) {
        $clk_new = join '_', $clk_output[$c];
        print Dumper $clk_new;
        push @clk_new, $clk_new;
    }
}

print Dumper @clk_new;
##</code><code>##

$VAR1 = [
          [
            'ux',
            'prim',
            'clk'
          ],
          [
            'ux',
            'side',
            'clk'
          ],
          [
            'ux',
            'xtal',
            'frm',
            'refclk'
          ]
        ];
$VAR1 = 'ARRAY(0x619920)';
$VAR1 = 'ARRAY(0x619920)';
$VAR1 = 'ARRAY(0x619920)';
$VAR1 = 'ARRAY(0x625700)';
$VAR1 = 'ARRAY(0x625700)';
$VAR1 = 'ARRAY(0x625700)';
$VAR1 = 'ARRAY(0x6929a0)';
$VAR1 = 'ARRAY(0x6929a0)';
$VAR1 = 'ARRAY(0x6929a0)';
$VAR1 = 'ARRAY(0x6929a0)';
$VAR1 = 'ARRAY(0x619920)';
$VAR2 = 'ARRAY(0x619920)';
$VAR3 = 'ARRAY(0x619920)';
$VAR4 = 'ARRAY(0x625700)';
$VAR5 = 'ARRAY(0x625700)';
$VAR6 = 'ARRAY(0x625700)';
$VAR7 = 'ARRAY(0x6929a0)';
$VAR8 = 'ARRAY(0x6929a0)';
$VAR9 = 'ARRAY(0x6929a0)';
$VAR10 = 'ARRAY(0x6929a0)';