use strict;
use warnings;

open my $fh, '<', 'an.ini' or die "Failed to open an.ini for reading: 
+$! <$^E>\n";

my (%settings, $head);
while (chomp(my $line = <$fh>)) {
    if ($line =~ /^\s*\[([^\[\]]+)\]\s*$/) {
        $head = $1;
    }
    elsif ($line !~ /^\s*$/) {
        push @{$settings{$head}}, $line;
    }
}

close $fh;

use Data::Dumper; print Dumper \%settings;
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