Add signal watcher system with power cycle triggers

signal-watcher

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+root_dir="$(readlink -f $1)"
+signal_dir="$root_dir/signals"
+trigger_dir="$root_dir/triggers"
+
+fswatch -0 --event=PlatformSpecific $signal_dir | while read -d "" event; do
+  signal="${event#"$signal_dir"}"
+  signal="${signal#"/"}"
+  trigger="$trigger_dir/$signal"
+
+  echo "Got signal: $signal"
+  if test -x "$trigger"; then
+    echo "Executing trigger"
+    "$trigger"
+  else
+    echo "No trigger found"
+  fi
+done

watcher/triggers/reboot

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+shutdown -r now

watcher/triggers/shutdown

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+shutdown -h now