As your Linux system runs, it captures logs of basically everything that goes on. You'd be surprised to know how much information Linux keeps in its logs, everything from logins, website look-ups, and even when USB devices are inserted and/or removed. This is great considering that if you run into problems, chances are that something in the logs may help you pinpoint where the error originated. This is especially true if an error shows up while booting but goes away quickly before you have a chance to read it.

Logs are kept in the /var/log directory. If you navigate to this directory and then list its storage, you'll see quite a few logfiles, each with their own purpose. The logfiles contained in this directory of interest in regards to troubleshooting include kern.log, dmesg, auth.log, boot.log, and syslog (these are explained later in this section). To read a log, type the cat command followed by the name of the log. Depending on the permissions of the log, you may...