How do I change the system to boot into text mode (runlevel 3) instead of the graphical login (runlevel 5)?

In order to change what runlevel the system boots to, modify the /etc/inittab file. This is a sample from the inittab file:

# Default runlevel. The runlevels used by RHS are:
# 0 - halt (Do NOT set initdefault to this)
# 1 - Single user mode
# 2 - Multiuser, without NFS (The same as 3, if you do not have networking)
# 3 - Full multiuser mode
# 4 - unused
# 5 - X11
# 6 - reboot (Do NOT set initdefault to this)
#
id:5:initdefault:
runlevel is determined by this line:

id:5:initdefault:
Change the above line to:

id:3:initdefault:and your system will now boot to runlevel 3 or text mode.