@list = (@list, bsd_glob ("$DIR/*XYZ", GLOB_QUOTE )); ...
push @list, bsd_glob ("$DIR/*XYZ", GLOB_QUOTE ));

##</code><code>##

use strict;
use warnings;

my $size = 1_000_000;

list_push();
#list_combine();

sub list_combine {
    print "Creating list1 ...\n"; my @list1 = ( "a" ) x $size;
    print "Creating list2 ...\n"; my @list2 = ( "b" ) x $size;
    print "Concatenating lists...\n";
    my $start = time;
    @list1 = (@list1, @list2);
    my $elapsed = time - $start;
    my $size = @list1;
    print "List size = $size, elapsed = $elapsed second(s)\n";
}

sub list_push {
    print "Creating list1 ...\n"; my @list1 = ( "a" ) x $size;
    print "Creating list2 ...\n"; my @list2 = ( "b" ) x $size;
    print "Pushing lists...\n";
    my $start = time;
    push @list1, @list2;
    printf "Elapsed = %d\n", time - $start;
    my $elapsed = time - $start;
    my $size = @list1;
    print "List size = $size, elapsed = $elapsed second(s)\n";
}