If and Decision making is done

regex.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+
+#provide one word/sentence as an argument to the script.
+#If in that sentence will be ip addresss, find out, if that
+#ip address is reachable or not.
+
+#argument check
+if [ $# -ne 1 ]; then
+    echo "Provide exactly one argument e.g. $0 argument"
+    exit 1
+fi
+
+VAR1=$1
+#ip address regex
+REGEX="[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[[:digit:]]{1,3}"
+
+#regex check
+if ! [[ $VAR1 =~ $REGEX ]]; then
+    echo "No IP address provided"
+    exit 2
+fi
+
+IP=${BASH_REMATCH[0]}
+
+#find if ip address is reachable or not
+ping -c4 $IP 1>/dev/null
+
+#1>/dev/null
+#It will redirect standard output and prevent
+#any output to print on screen.
+
+if [ $? -eq 0 ]; then
+    STATUS="ALIVE"
+else
+    STATUS="DEAD"
+fi
+
+echo "IP found: $IP ($STATUS)"