Rev1976,
the easiest way to add user to Linux is by command:
useradd -g db2grp1 -m -d /db2home/db2inst1 db2inst1 -p password1
Notes:
-g db2grp1 -> add user to this group
-m -d /db2home/db2inst1 -> create home directory
db2inst1 -> new user name
-p password1 -> password
If user already exists and you would like to change password:
passwd userid
Note:
userid -> userid you would like to change password
P.S. I recommend the following web site for Unix/Linux commands:
http://www.computerhope.com/unix.htm
Hope this helps,
Grofaty