If your HTTP server is running behind Cloudflare, it is recommended to only allow traffic from Cloudflare IP addresses. We can config this systematically using iptables. However, it's also flexible to white list Cloudflare IPs just inside the Nginx service.

A simple command to uninstall php and related packages on Ubuntu.

GoAccess is a tool for monitoring web server logs in realtime, which written in C and can be accessed directly from the command-line. With GoAccess you can view or analyse relevant statistics quickly and securely. Apart from the command-lin dashboard interface, it's also capable of displaying the statistics in other formats such as HTML, JSON, and CSV, which you can use in other contexts.

In markdown notes, it's easy to insert simple mathematical formulas with plain LaTeX. However, I'm always forget some basic characters for equations. So, let's take a short review based on the note "LaTeX math for undergrads".

Log rotation is a process of removing/storing old logs while not affecting the latest logs. Almost every single application generates meaningful logs, and if not properly handled, logs can eat up all the space on your disk. Here comes the Logrotate.