在測試服務器（Red Hat Enterprise Linux Server release 6.6）需要安裝桌面系統環境，於是選擇GNOME桌面環境安裝。
一：檢查系統的運行級別以及是否安裝了桌面環境
[root@localhost ~]# runlevel
N 3
[root@localhost ~]# yum grouplist | more
Loaded plugins: product-id, security, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-
manager to register.
Setting up Group Process
Installed Groups:
Additional Development
Base
Console internet tools
Directory Client
E-mail server
Fonts
Graphical Administration Tools
Hardware monitoring utilities
Java Platform
Large Systems Performance
Legacy UNIX compatibility
Legacy X Window System compatibility
NFS file server
Network file system client
Networking Tools
PHP Support
Performance Tools
Perl Support
Scientific support
Security Tools
Server Platform
System Management
System administration tools
TurboGears application framework
Web Server
也可以使用下面命令驗證是否安裝桌面環境組件
[root@localhost ~]# ps -A | egrep -i "gnome|kde|mate|cinnamon|lx|xfce|jwm"
[root@localhost ~]#
二：安裝桌面環境相關軟件組
使用yum grouplist 可以看到有Desktop、Desktop Platfrom、X Window System、Graphics Creation Tools等桌面環境有關的軟件組件可以安裝
[root@localhost ~]# yum groupinstall "Desktop" "Desktop Platform"
[root@localhost ~]# yum groupinstall "X Window System" "Graphics Creation Tools"
三：修改系統的啟動級別為 5
[root@localhost ~]# vi /etc/inittab
# inittab is only used by upstart for the default runlevel.
#
# ADDING OTHER CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# System initialization is started by /etc/init/rcS.conf
#
# Individual runlevels are started by /etc/init/rc.conf
#
# Ctrl-Alt-Delete is handled by /etc/init/control-alt-delete.conf
#
# Terminal gettys are handled by /etc/init/tty.conf and /etc/init/serial.conf,
# with configuration in /etc/sysconfig/init.
#
# For information on how to write upstart event handlers, or how
# upstart works, see init(5), init(8), and initctl(8).
#
# 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)
#
id:3:initdefault:
將系統的啟動級別從3修改為5，然后重啟系統后，重啟過后出現下面界面，按照提示操作即可。操作完成后重啟系統即OK。
