adding a user under redhat using adduser
two basic steps:-
# adduser yournewusername
(wait for command prompt)
# passwd yournewusername
(you will now be prompted to enter and confirm a password)
there’s a whole load of other options, but this will do the basic creation of the user including adding their home directory.
update:
Ok firstly according to my book you should be using useradd rather than adduser, also you need to be logged in as root and you must do that by using su - rather than just su e.g:-
#su - root
then
#useradd whatever
see this post for more details