diff --git a/multi-upload.pl b/multi-upload.pl
new file mode 100644
index 0000000..a300eba
--- /dev/null
+++ b/multi-upload.pl
@@ -0,0 +1,87 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+use autodie;
+use Time::HiRes qw(sleep);
+use POSIX qw(strftime);
+
+if (!@ARGV or $ARGV[0] ne "--please-destroy-my-data") {
+    print "DANGER! Please read and understand the source code before using.\n";
+    print "Regular users do not need to use this program. Use 'pio run' instead.\n";
+    exit 1;
+}
+
+my %pane;
+my $command = "";
+
+sub printlog {
+    print strftime("%Y-%m-%d %H:%M:%S", localtime), " @_\n";
+}
+
+sub spawn {
+    my ($dev) = @_;
+
+    printlog "Spawning $dev";
+
+    my $c = $command;
+
+    $c =~ s[ttyUSB\w+][$dev];
+    $c =~ s/^/time /;
+    $c =~ s[$][| perl -pe"BEGIN { \$/ = \\1 } s/\\r/\\n/"; echo "-- $dev done --"; read a];
+
+    $pane{$dev} = readpipe qq{tmux split-window -d -h -P -F '#{pane_id}' '$c'};
+    chomp $pane{$dev};
+
+    system "tmux select-layout even-horizontal";
+}
+
+if (1 < (() = glob("/dev/ttyUSB*"))) {
+    die "Disconnect USB serial devices except one target device.\n";
+}
+
+if ($ARGV[-1] ne "it's-a-me") {
+    exec qw[tmux new perl], $0, @ARGV, "it's-a-me";
+}
+
+my $pio_pid = open my $pio, "-|", "pio run -v -t upload";
+while (defined(my $line = readline $pio)) {
+    print $line;
+    if ($line =~ /esptool/ && $line =~ /write_flash/) {
+        $command = $line;
+        system "pkill -9 -P $pio_pid";  # kill upload process.
+        kill 9, $pio_pid;
+        last;
+    }
+}
+
+if ($command =~ /(ttyUSB\d+)/) {
+    spawn $1;
+} else {
+    warn "Could not snatch upload command.\nMake sure a single target device is already connected.\nPress enter to exit.\n";
+    scalar <STDIN>;
+    die;
+}
+
+open my $monitor, "-|", "udevadm monitor --kernel --subsystem-match=usb-serial";
+
+printlog "Started monitoring for new usb-serial devices.";
+
+
+while (defined(my $line = readline $monitor)) {
+    my ($event) = $line =~ /\b(remove|add)\b/ or next;
+    my ($dev) = $line =~ /(ttyUSB\d+)/ or next;
+
+    if ($event eq 'add') {
+        while (!-w "/dev/$dev") {
+            sleep .1;
+            # wait for permissions to settle;
+        }
+
+        spawn($dev);
+    } else {
+        if (exists $pane{$dev}) {
+            printlog "Killing $dev";
+            system "tmux kill-pane -t $pane{$dev}";
+        }
+    }
+}