added last question answer

bash3.sh

+#!/bin/bash
+
+
+
+ip_range=$1
+start_ip=$(echo "$ip_range" | cut -d'-' -f1)
+end_ip=$(echo "$ip_range" | cut -d'-' -f2)
+start=$(echo "$start_ip" | cut -d'.' -f4)
+end=$(echo "$end_ip" | cut -d'.' -f4)
+if (( start >= 0  && end <= 256 && start <= end ))
+then
+    for ((n=start; n<=end; n++)); do
+        host="192.168.0.$n"
+        ping -c2 "$host" &> /dev/null
+        if [ $? = 0 ]; then
+            echo "$host is UP"
+        else
+            echo "$host is DOWN"
+        fi
+    done
+else
+    echo "incorrect ip range, use the format 192.168.0.startnumber-192.168.0.endnumber"
+fi