I know that in Linux/Unix the pipe is very useful. For example to find a process that is running you would use ps- ef|bf2. This basically searches all the processes that are running and looks for the ones that contain BF2. Another thing that I did not think about until I looked at computerhope.com, is that in programming a double pipe (||) can be used as the OR operator. So, you can say somthing like if (x=something) || (y=everything), it can make programming a little quicker, and easier.