SSL  TLS  HTTPS  Lets Encrypt  Reference  Certbot 

A handful of commonly used Certbot commands used for managing Let's Encrypt certificates.

Reference  Markdown 

Quick reference for for Markdown syntax. Markdown is a simple markup language used for composing text documents.

PHP  Regular Expressions  Reference 

Quick reference for using regular expressions in PHP.

Vim  Reference  cheatsheet 

vim Information / Reference / Cheatsheat