adding function to switch DNS nameservers + monitoring of current settings; adding a README

README.md

@@ -0,0 +1,46 @@
+# Dynamic Status
+
+These scripts control and monitor several functions of my computer. Most importantly it is possible to switch to a "offline status" which disables several internet-using monitoring functions.
+
+status-ip.sh and status-misc.sh rely on `xfce-genmon-plugin` to show some status messages on the XFCE task bars.
+
+status-interaction.sh enables users to actively change some values, e.g. the on-/offline status, the used DNS nameserver, and to trigger some actions, e.g. to send mails in an `msmtp` queue.
+
+I tried to make it as compatible to as many systems as possible but some values are still hard-coded.
+
+## DNS nameserver switch
+
+This feature heavily depends on network-manager and it's dispatcher feature. In order to use it, put a file in `/etc/NetworkManager/dispatcher.d/` and name it `90-custom-resolv.conf` for example. Fill it:
+
+```
+#!/bin/bash
+#
+# Depending on dynamic status, override /etc/resolv.conf
+
+CUSTOM=/tmp/resolv_custom.conf
+DEFAULT=/home/user/bin/default-nameserver.sh
+
+if [ ! -e $CUSTOM ]; then  # if file does not exists, use default nameserver script
+  bash $DEFAULT
+  echo "# 90-custom-resolvconf executed default-nameserver.sh" >> /etc/resolv.conf
+  exit 0
+fi
+
+SET=$(cat $CUSTOM | head -n1 | awk '{print $NF}')  # first line, last word
+
+if [ "$SET" != "auto" ]; then
+  cp -f /etc/resolv.conf /etc/resolv.conf.bak   # backup original resolv config file
+  cat $CUSTOM > /etc/resolv.conf  # use custom file, update original one 
+else
+  echo "# 90-custom-resolvconf didn't change any substantial values here, just added this line." >> /etc/resolv.conf
+fi
+
+```
+
+The file has to be owned by root and be executable in order to function. It will either execute a script that sets default nameserver settings (in my case, it's localhost since I use a local dnsmasq), or take the values from another file which is created by switching the nameservers with status-interaction.sh.
+
+Nameservers can be configured in `config.cfg` as value of `NS=`. It holds following pattern: 
+
+`set1(ip1,ip2,ip3)|set2(ip4,ip5)`
+
+Please remember to put it between quotes.