To create a new admin user on a Linux system, use these commands:

sudo adduser -d /home/USERNAME -m USERNAME 
sudo passwd USERNAME
sudo chown -R  /home/USERNAME
sudo usermod -G wheel,apache USERNAME #wheel is admin group for Redhat/Centos
sudo passwd USERNAME

To create a new non-admin dev user, user this instead:

sudo adduser -d /home/USERNAME -m USERNAME
sudo passwd USERNAME
sudo chown -R  /home/USERNAME
sudo usermod -G dev,apache USERNAME
sudo passwd USERNAME