SysAdmin

A quick bash one-liner to pull offending IP addresses from exim relay-denied entries and resolve them to hostnames, making it easier to identify which gateways are misconfigured.

Use iptables string matching and the recent module to drop connections from abusive bots that exceed a request threshold within a short window.

A quick bash one-liner to identify which directories are consuming the most inodes on a Linux system, helping you pinpoint the source of ‘No space left on device’ errors when disk space still appears available.

A quick one-liner to identify the ten largest files or directories under any path. Useful when disk space is tight and you need to find what is eating your storage.

A quick way to list every port a process is listening on, using lsof and a simple grep filter. Handy for troubleshooting connectivity issues or auditing what services are exposed on a host.

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.