install lets encrypt certificate for 90 days free

installletsencrypt.sh

// INSTALL LETSENCRYPT ON UBUNTU 16.04

sudo apt update && sudo apt upgrade

# IGNORE if git already installed (to check git --version)
sudo apt-get install git

sudo git clone https://github.com/letsencrypt/letsencrypt /opt/letsencrypt

cd /opt/letsencrypt

sudo -H ./letsencrypt-auto certonly --standalone -d example.com -d www.example.com

# write email address if asked.
# press enter then agree terms condition then n for saying not to share email address.

#check your Certificate  domain

sudo ls /etc/letsencrypt/live

# all the domain covered under this single certificate
./certbot-auto certificates


#####################################################
#### For Renew in 90 days lifespan 
#####################################################

cd /opt/letsencrypt

sudo -H ./letsencrypt-auto certonly --standalone --renew-by-default -d example.com -d www.example.com