This article compares and contrasts the Unix OS with Windows OS in terms of stability, performance, compatibility, and reliability. It also discusses the advantages and disadvantages of using open source OS. The article also covers OS administration using command line interface (CLI) and security related commands. It provides information on creating files and directories, changing file permissions, resetting user passwords, and using networking commands like ping, ifconfig, netstat, nslookup, hostname, and ARP.