Change Linux run level

On systemd (including RedHat) do the following;

Text Only

ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target

Graphical Envirment

ln -sf /lib/systemd/system/graphical.target /etc/systemd/system/default.target

UNIX System V (including Solaris and Slackware), do the following;

Edit /etc/inittab

Look for the section Default Runlevel

and edit the line that follows (normally 3 for multiuser mode, 4 is X11 and 1 is single user mode)