Gathering network information and connectivity diagnostics

In this section, we are going to test IPv4's connectivity and write scripts for it.

Getting ready

Besides having a terminal open, we need to remember a few concepts:

• The If..Else condition case in shell scripting
• IP address of the device
• curl command must be installed (you can install it by using the following command: sudo apt install curl)

The purpose of this section is to show you how you can check network connectivity.

How to do it...

1. Open a terminal and create the test_ipv4.sh script:

if ping -q -c 1 -W 1 8.8.8.8 >/dev/null; then
  echo "IPv4 is up"
else
  echo "IPv4 is down"
fi

2. Now, to test IP connectivity and DNS, create a script called test_ip_dns.sh:

if ping -q -c 1 -W 1 google.com >/dev/null
then
  echo "The network is up"
else
  echo "The network is down"
fi

3. Lastly, create a script called test_web.sh to test web connectivity:

case "$(curl -s --max-time 2 -I http://google.com | sed 's/^[^ ]*  *\([0-9]\).*/\1/; 1q')" in
  [23]...