Boot systems into different runlevels manually

To change the runlevel of a single boot session, use the following instructions:

• When the GRUB menu bypass screen appears at boot time, press any key to enter the GRUB menu (within the first three seconds).
• Press the a key to append to the kernel command.
• Add <space><runlevel> at the end of the boot options line to boot to the desired runlevel. For example, the following entry would initiate a boot process into runlevel 3

[ Minimal BASH-like line editing is supported. For the first word, TAB lists possible command completions. Anywhere else TAB lists the possible completions of a device/filename. ESC at any time cancels. ENTER at any time accepts your changes.]

grub append> ro root=/dev/mapper/vg_ ......... rhgb quiet 3

# runlevel 0 is System halt (Do not use this for initdefault!)
# runlevel 1 is Single user mode
# runlevel 2 is Local multiuser without remote network (e.g. NFS)
# runlevel 3 is Full multiuser with network
# runlevel 4 is Not used
# runlevel 5 is Full multiuser with network and graphic
# runlevel 6 is System reboot (Do not use this for initdefault!)