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

status-interaction.sh

@@ -34,9 +34,58 @@ function switch_conn {
   fi
 }
 
+# SWITCH NAMESERVERS
+function switch_ns {
+  read -p "Switch nameservers? [Y/n]: " YN
+  if [[ $YN =~ ^(Y|y|)$ ]]; then
+    NS_SETS=$(echo "$NS" | grep -o "|" | wc -l)   # number of nameserver sets (separated by |)
+    NS_SETS=$(expr $NS_SETS + 1)                  # add number +1 to correct count
+    
+    for ((i = 1; i <= $NS_SETS; i++)); do   # circle through all nameserver sets and number them
+      NS_NAME[$i]=$(echo $NS | cut -d"|" -f$i | sed -E 's/(^.+?)\((.+?)\)/\1/')
+      NS_VALUE[$i]=$(echo $NS | cut -d"|" -f$i | sed -E 's/(^.+?)\((.+?)\)/\2/')
+      
+      echo "$i. ${NS_NAME[$i]}"
+    done
+    
+    NS_NAME[0]="auto"; NS_VALUE[0]=""
+    echo "0. ${NS_NAME[0]} (DHCP-given)"
+    
+    # Choose nameserver number and verify selection
+    OK=0
+    while [ "$OK" != "1" ]; do
+      echo; read -p "Type number of nameserver set: " i
+      
+      if [ "${NS_NAME[$i]}" == "" ]; then
+        OK=0
+        echo "A nameserver set with this number does not exist. Please choose again."
+      else
+        OK=1
+        echo "Nameserver set switched to \"${NS_NAME[$i]}\". Please reconnect with NetworkManager to put the changes into effect."
+      fi
+    done
+    
+    # Set definite values
+    NS_NAME=${NS_NAME[$i]}
+    NS_VALUE=${NS_VALUE[$i]}
+    
+    NONS=$(echo "$NS_VALUE" | grep -o "," | wc -l)  # number of nameservers in chosen set
+    NONS=$(expr $NONS + 1)
+    
+    echo "# Custom nameserver set: $NS_NAME" > /tmp/resolv_custom.conf  # write custom resolv config, which will be interpreted by "90-custom-resolvconf"
+    
+    for ((i = 1; i <= $NONS; i++)); do
+      echo "nameserver $(echo $NS_VALUE | cut -d"," -f$i)" >> /tmp/resolv_custom.conf
+    done
+  
+    var_ns=$NS_NAME   # save name of nameserver set for later update of status file
+    
+  fi  # / YN
+}
+
 # OPTION SCREEN
 function exec {
-  ACTIONS=("send mails in queue" "list mails in queue" "switch connection status [$var_conn]" "quit")
+  ACTIONS=("send mails in queue" "list mails in queue" "switch connection status [$var_conn]" "switch nameservers" "quit")
   PS3="Select action: "
   
   select action in "${ACTIONS[@]}"
@@ -52,7 +101,10 @@ function exec {
       3) # Switch online status
       switch_conn
       break ;;
-      4|"q") # exit silently, one can also press "q" instead of the number
+      4) # Switch nameservers
+      switch_ns
+      break ;;
+      5|"q") # exit silently, one can also press "q" instead of the number
       exit 0
       break ;;
     esac