well, to sum it up. 'root' is a user on every *nix computer. it is like the administrator.
'root' knows (can see/read) anything, and can do anything to any user, file or directory.
look on google.com/linux about root.. also check here
for the (brief
)explanation of 'root' from the Slackbook (or even read all of it! very informative)
what they are saying is that you have to be an administrator (root) in order to run that command, for security reasons. so you have to login as the root user then you will be allowed to do anything, and can do the command you are asking about. open a terminal and type su or sudo:
[enter root password]
check the man page for su
to learn about it. in each case, after you type 'su' or 'sudo' you will be prompted to enter the root users password for verification. you can then execute the command 'as root [user]'.
notice in my code sample above the last character in the prompt (the '$'). the ampersand lets you know that your just a normal user (or any user but root). when i entered the su command and entered root's password the prompt switched to a pound sign/'#'. it does this so you notice that your currently 'root' when your typing commands in. be VERY careful when you are root.. anything and everything you do CAN happen, WILL happen, and CANT be undone (well,.. ya.. lets leave it at that
when your done entering your commands, type 'exit' (or 'logout') at the terminal to stop being root, and come back to your sense as yourself and the normal user you are.. youll notice the prompt will switch back to the '$'. also.. as it mentions in the slackbook link i posted.. only become root when necessary, and never log in as root into your gui.
but search google.com/linux or somewhere about root, su, and sudo first. but thats a _very_ brief overview.
REMEMBER:: i havent really emphasized how powerful root is here.. but as i said, root can do any
thing. please read up about it to realize this, or learn the hard way!