Using sdiff like a pro

My colleague Kiran Patel, has showed me this really cool command: superdiffcommand=’systemctl list-units –type=service | grep running’ && sdiff -w 200

Puppet – External Facts

External facts is a great way to attach (arbitrary) metadata to a machine during the the launch of a new machine. E.g. when building a Centos 7 aws ec2 instance, you can generate the external facts via userdata. Puppet can use these external facts in the way as any other […]Read more »

ssh tunnel

Create an ssh tunnel like this: $ ssh -L 8081:localhost:80 {fqdn} Then access the server’s website using: http://localhost:8081

Data Packets, packet headers, and the OSI model

A public IP address allows a machine to be accessible from the internet, whereas a private IP address allows machine to be accessible by other machines that are also attached to the same network.

Using arp

This is a quick guide to using the telnet command.