In Unix-like systems, a daemon is a process that runs in the background, usually providing some kind of service. Most daemons can be identified in the process list because their names end in d. Examples are the Apache web server (httpd) and the OpenSSH server (sshd). Another thing daemons usually have in common is that they are written in the C programming language. To create a daemon quickly, you can throw one together using the Bourne Again Shell (Bash) scripting language.

In Mac OS X, the root account is disabled by default. The first user account created is added to the admin group and that user can use the sudo command to execute other commands as root. The conventional wisdom is that sudo is the most secure way to run root commands, but a closer look reveals a picture that is not so clear.

Sar is the "system activity report" program. In Linux, it is usually found in the sysstat package. The sysstat package includes programs and scripts to capture and summarize performance data, then produce detailed reports. This suite of programs can be very useful in tracking down performance bottlenecks and providing insight into how the system is used throughout the day.