commit 4ccfee47dfa0a78aacf9e8dad2391be6a128eeb1
Author: Joachim Lusiardi <joachim@lusiardi.de>
Date:   Thu Sep 12 15:33:07 2019 +0200

    add script

diff --git a/react_to_ip_change.sh b/react_to_ip_change.sh
new file mode 100644
index 0000000..241ca52
--- /dev/null
+++ b/react_to_ip_change.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+
+IP_FILE='/tmp/ipaddress'
+
+[[ -f "${IP_FILE}" ]] && IP_OLD="$(< "${IP_FILE}" )"
+
+IP_NEW="$(curl -s -4 http://icanhazip.com/)"
+
+# work around to report IP to root server
+ssh wiebelbach@lusiardi.de -i ~/.ssh/id_rsa_update_ip "echo $IP_NEW > IP"
+
+if [[ "${IP_OLD}" != "${IP_NEW}" ]]; then
+        echo "change from ${IP_OLD} to ${IP_NEW}"
+        echo ${IP_NEW} > ${IP_FILE}
+        for SCRIPT in `ls /usr/local/etc/ipchange.d/*.sh`
+        do
+                ${SCRIPT} ${IP_NEW}
+        done
+else
+        echo "no update required (still ${IP_OLD})"
+fi
+