As a webmaster chances are you will wind up managing a Linux box or two in your time – and when you do you’ll be happy you learned these tricks.
The Bash Shell
Discover how to use pipelines to string together a series of commands. This means that the output from the first command in the pipeline is used as the input for the second command in the pipeline. The output from the second command in the pipeline is used as the input to the third command in the pipeline, and so on, and so on.
Learn how Bash keeps track of a certain number of previous commands that you have entered into the shell via the History; and see how Bash makes life easier for you is by supporting command aliases – commands that the user can specify.
Learn how to use wildcards and command line completion to make your life programming within Bash that much easier.
The rwhod daemon is a process that allows a remote user to see who is logged into your system. The client program is rwho. It has many of the same security problems as the finger daemon. For a cracker use of rwho could allow him to watch for times on your system when nobody is logged in and begin his attacks. Learn how to turn off RWHOD on your server.
A detailed list which shows the majority of the more popular known trojans, and the ports they normally use.
Learn how to be able to view all the running processes, or stop a program if it hits a bug or a flaw.