perl script now takes --daemon as a flag

...also figures out the number of CPUs on its own.

loaduino.pl

@@ -2,10 +2,18 @@
 
 use strict;
 use warnings;
+use 5.10.0;
 
 use Device::SerialPort;
+use POSIX qw(setsid);
 
-my $device = '/dev/ttyUSB0';
+# daemonize
+if (defined($ARGV[0]) && $ARGV[0] eq '--daemon') {
+  daemonize();
+}
+
+my $device   = '/dev/ttyUSB0';
+my $cpucount = countcpus();
 
 # connect to the port
 my $port = Device::SerialPort->new($device)
@@ -23,13 +31,27 @@ while (1) {
   my $val = pack('s', $load);
 
   my $count_out = $port->write($val);
-  print "$load degrees, $count_out bytes\n";
+  # print "$load degrees, $count_out bytes\n";
   sleep 1;
 }
 
-sub getdegrees {
-  my $cpucount = 2;
 
+
+sub countcpus {
+  open my $fh, '<', '/proc/cpuinfo'
+    or die "Can't get cpu info: $!";
+  my @cpuinfo = <$fh>;
+  close $fh;
+
+  my $count = 0;
+  foreach (@cpuinfo) {
+    $count++ if /^processor\s+: [0-9]/;
+  }
+
+  return $count;
+}
+
+sub getdegrees {
   open my $fh, '<', '/proc/loadavg'
     or die "Can't get load: $!";
   my $avg = <$fh>;
@@ -37,12 +59,25 @@ sub getdegrees {
 
   my ($load) = split / /, $avg;
 
-  my $pct;
+  my $percent;
   if ($load < $cpucount) {
-    $pct = $load / 2;
+    $percent = $load / $cpucount;
   } else {
-    $pct = 1;
+    $percent = 1;
   }
 
-  return int($pct * 180);
+  return int($percent * 180);
+}
+
+sub daemonize {
+  chdir '/';
+  umask 0;
+  open STDIN, '/dev/null';
+  open STDOUT, '>', '/dev/null';
+  open STDERR, '>', '/dev/null';
+  defined(my $pid = fork)
+    or die "Can't fork: $!";
+  exit if $pid;
+  setsid
+    or die "Can't start a new sesssion: $!";
 }