use Data::Dumper;

$file = "/tmp/data.txt";
$my_freezevar = [1,2,3,4];

# to freeze to disk
open (FILE, ">$file");
print FILE Data::Dumper->Dump( [$my_freezevar], ["data"] );
close FILE;

# to thaw
open (FILE_2, "$file");
$/ = ""; #gets rid of newlines as line separator
$my_thaw_var = eval ( <FILE_2> );
close (FILE_2);

print Dumper($my_thaw_var);