@diary_entry = keys %{$diary_data[0]};
for $temp (@diary_entry) {
    print "$temp\n";
}

##</code><code>##

$ ./send_referral.pl 0000079100
Diary ID: 536870914
timestamp
value
user

##</code><code>##

print "$temp: $diary_data[0]{$temp}\n";

##</code><code>##

$ ./send_referral.pl 0000079100
Diary ID: 536870914
Use of uninitialized value at ./send_referral.pl line 201.
timestamp: 
Argument "NWORLASTE800 LOGIN FAILED\nNWORLASTE801 LOGIN FAIL\n\nWA..." isn't numeric in helem at ./send_referral.pl line 201.
Bad index while coercing array into hash at ./send_referral.pl line 201.
$
##</code><code>##

@diary_entry = values %{$diary_data[0]};
print "@diary_entry\n";

##</code><code>##

 # Another try:
    my %hash = %{$diary_data[0]};
    @diary_entry = keys %hash;
    #@diary_entry = keys %{$diary_data[0]};
    print "@diary_entry\n";
    for $temp (@diary_entry) {
        print "$temp\n";
    }