use DBM::Deep;
my $file ='foo.db';
unlink $file if -e $file;
my %h;
tie %h, 'DBM::Deep', {file=>$file,autoflush=>1};
$h{key} = 'value';
untie %h;
tie %h, 'DBM::Deep', {file=>$file,autoflush=>1};
print $h{key};