Scalar value @msgs[0] better written as $msgs[0] at f1.pl line 5.

##</code><code>##

use strict;
use warnings;
use Data::Dumper;
my @msgs;
push @msgs, [ "1st array: line 1", "1st array: line 2" ];
push @msgs, [ "2nd array: line 1", "2nd array: line 2", "2nd array: line 3" ];
print Dumper(\@msgs);
my $i = 0;
for my $arr (@msgs) {
   ++$i;
   print "array $i:\n";
   for my $line (@{$arr}) {
      print "  $line\n";
   }
}