useradd.sh

useradd app_user
passwd app_user
vi /etc/sudoers  #open sudoers in your favorite text edit
# add the following line below "root ALL=(ALL) ALL" :
# app_user ALL=(ALL) ALL
# save file and exit

#disable root login from ssh, so nobody is able to brute force a root login
vi /etc/ssh/sshd_config
#uncomment "PermitRootLogin yes" and change it to "PermitRootLogin no"
/etc/init.d/sshd restart

#logout and login or su to your new user
su app_user
cd ~