Say you bught a new hard drive and want to copy the home directories to the new drive, or perhaps you are just using the cp command to create a quick and dirty backup of a directory. Now you got a problem. First, you should do it recursively while the cp command doesn't do it recursively by default. Second, you also need to preserve ownership and permissions. The solution is to use the command the following way:

cp -rp [src] [dest]