Ubuntu
# runlevel
N 2
* 0 System Halt
* 1 Single user
* 2 Full multi-user mode (Default)
* 3-5 Same as 2
* 6 System Reboot
CentOS/RHEL
# Default runlevel. The runlevels used 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)
#
런레벨 관리
