Bash

A quick one-liner to group running processes by name and rank them by memory usage. Handy when you need to spot which services are eating RAM without pulling up a full top or htop session.

A lightweight bash script that monitors Apache error logs for repeated access-denied entries and automatically blocks offending IPs via iptables. Useful for quick-and-dirty rate-based blocking without a full WAF.

A quick workflow for triggering a DNS zone reload with rndc and confirming the result in the system log. Covers the two commands you need and what to look for in the output.

Learn how to mount a filesystem by its label in /etc/fstab so your mount points stay stable across reboots and hardware changes.

A Perl-based utility that emulates a busy server by spawning multiple threads performing varied IO workloads. It uses direct IO and cache invalidation to benchmark raw disk performance in a multitasking environment.

A quick walkthrough of using mtr in report mode to capture packet loss data across network hops. Learn how to run a 30-cycle test and read the output to isolate where loss is occurring.