Sometimes you need to get an IP address of the VM from inside of it. You can do this relatively simple from Azure VM with curl and jq thanks to Metadata endpoint as described in this document https://azure.microsoft.com/en-us/blog/announcing-general-availability-of-azure-instance-metadata-service/
And if you need the public IP address of interface eth0 this is the command:
curl -H Metadata:true http://169.254.169.254/metadata/instance?api-version=2017-04-02| jq '.network.interface[0].ipv4.ipAddress[0].publicIpAddress'
