Send a POST request to the URL https://www.random.org/strings/?num=1&len=16&digits=on&upperalpha=on&loweralpha=on&unique=on&format=plain to generate a random string of 16 characters containing both upper and lower case letters and digits.
curl -sLX POST https://www.random.org/strings/?num=1\&len=16\&digits=on\&upperalpha=on\&loweralpha=on\&unique=on\&format=plain