Ten Powerful Linux Commands

Today is the last day in 2009, I have no idea what should I do but just want to pray that my family, relatives and bosom  friends would have a sweet life in the next year. Linux is a 2nd OS in my life, there are always something new can make me  feel awesome, so I think that with continuous interests it brings to me I believe that I will do well in it though some  obstacles may often encountered when using it. Following article is digged from digg website that I think it's helpful to me  and post it here hoping the author do not mind. The original article's link is http://laptoplogic.com/resources/ten-powerful -linux-commands
This article is equal parts opinion and fact, as the most powerful commands depends on what one needs them for; someone who  is running a network of Linux machines will require different commands than an individual user. With that said, without  regard to opinion, many commands are powerful, and any Linux user would do well to know them. Below are ten such commands,  all simple in nature but powerful in their usefulness. The method in which they are executed will depend on the Linux system  used. For example, you may need to use su instead of sudo or nothing at all, if you're running as root. Note: to see a full  list of possibilities for commands, type 'command - -help' in the Terminal.
1. PS
The PS command is a powerful command, and its power comes from its utter versatility. The PS command means 'process status',  and displays everything to do with processes; think of it as the task manager of geeks. There are many variations of PS that  can be used, such as the common PS AUX, which will pull a Terminal list of all running processes, or PS AUX | GREP PID to  pull up a specific process. Used in conjunction with the kill command allows users to end processes.
2. RM -RF
This command is, quite possibly, the most powerful command, as it can destroy entire systems in the wrong hands