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David Cao

David is a Cloud & DevOps Enthusiast. He has years of experience as a Linux engineer. He had working experience in AMD, EMC. He likes Linux, Python, bash, and more. He is a technical blogger and a Software Engineer. He enjoys sharing his learning and contributing to open-source.

How to Fix “zsh: command not found: codex”

You install the OpenAI Codex CLI, open a new terminal, type codex—and zsh throws this back at you: This error is almost never a broken installation. It simply means your shell can’t find an executable named codex in any directory listed in your PATH. There…

Filtering UDP Packets with the tcpdump Command

tcpdump is a powerful command-line packet analyzer that lets you capture and inspect network traffic in real time. When you need to troubleshoot services like DNS, DHCP, or NTP, filtering for UDP packets is often the quickest way to see what’s…