Update: Added simulation.

Update: Changed to ! exists ...

Looping and grep'ing for each temp file is likely expensive. This populates @newarray with new files only.

# this hash has list (keys) of all the files previously processed
my %processed = map { $_ => 1 } @arraytocompare;

my $path = "/tmp/testpatch";
opendir DIR, $path or die $!;

# in this array i get all the new files which i need to process now
my @newarray = map { ! exists $processed{$_} ? $_ : () } readdir DIR;

closedir DIR;
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The above is simulated below and outputs 8000 taking just a fraction of a second to complete.

# this hash has list (keys) of all the files previously processed
my %processed = map { $_ => 1 } 100001 .. 108000;

# in this array i get all the new files which i need to process now
my @newarray = map { ! exists $processed{$_} ? $_ : () } 108001 .. 116
+000;

print scalar @newarray, "\n";
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