I was reading the instructions, yet there is no example for me to understand how to insert a timestamp. I require Unix timestamp or any type of a date that I can format myself.
http://nginx.org/en/docs/http/ngx_http_ssi_module.html#commands
The final goal is to have timestamp inserted in a manner how I like it, to prevent the contact form abuse. And in case that spammers adopt to it, I would change the format.