#!/usr/bin/perl --

## Config
#Set the path to your tracks directory, this must contain an 'in' folder, an 'nmea' folder, and a 'gpx' folder.
$tracksPath = "<PathToTracksFolder>";

local(*DIR);
opendir DIR, "$tracksPath/in";

my @files = grep {-f "$tracksPath/in/$_" } readdir DIR;
close DIR;

foreach (@files){
   $track = $_;
   if ($track =~ /.txt\Z/i) {
      #move to nmea folder
      `mv $tracksPath/in/$track $tracksPath/nmea/$track`;
   }
}

#Create a master files with all of your tracks.
opendir DIR, "$tracksPath/nmea";

my @files = grep {-f "$tracksPath/nmea/$_" } readdir DIR;
close DIR;

sort @files;
open (NMEA, ">$tracksPath/nmea.txt");
foreach (sort {$a <=> $b} @files){
   
   $str = "";
   open(FILE, "$tracksPath/nmea/$_");
   while (<FILE>) {
      $str .= $_;  
   }
   close FILE;
   print NMEA $str;
}

close (NMEA);

#Convert to a master GPX
`gpsbabel -i nmea -f $tracksPath/nmea.txt -o gpx -F $tracksPath/gpx.gpx`;