Linux experience. I have run a decent amount of Linux experience, having competed in CyberPatriot as the only Linux (Ubuntu) operator and taken my team to Nationals. I also helped maintain Fedora servers at Metier Defense Solutions when I was there and running all of the infrastructure at NanoTech Computers. NanoTech runs CentOS and Ubuntu. I'm mainly proficient in Ubuntu. My backup laptop/travel laptop is Ubuntu 14.04.
System Hardening. I worked on Windows, Linux, and Cisco iOS routers. After CyberPatriot and moving into CCDC I keep a focus on understanding configurations made to a system, how it impacts the operational mission of the parent organization, and the security implications of each setting. Two things I focus on is the concept of least privilege and future proofing.