Utiliser le module FileHandle, entourer les valeurs du hash entre deux accolades :
#!/usr/local/bin/perl
use strict;
use FileHandle;
my %hash;
$hash{'1'} = FileHandle -> new("1.file","a")
or die $!;
$hash{'2'} = FileHandle -> new("2.file","a")
or die $!;
print {$hash{'1'}} "un\n";
print {$hash{'2'}} "deux\n";
while(my($key,$value) = each(%hash))
{
$value -> close() or warn $!;
}