【圖形介面】Linux安裝圖形介面

* 安裝圖形介面
```
yum groupinstall -y "GNOME Desktop"
```
|run level|<|h
|0|關機(``不可設為預設``)|
|6|重新開機(``不可設為預設``)|
|1|單人文字模式|
|2|多人模式文字(無網路)|
|3|多人模式文字(有網路)|
|4|客製化模式3|
|5|多人模式圖形(有網路)|
```
系統使用"targets"取代以前的"run-levels"。下列為主要的兩個設定值：
multi-user.target: 表示 runlevel 3
graphical.target: 表示 runlevel 5

檢查現在系統的預設target的指令：systemctl get-default
```
*查看現在啟動
```
[snowFlake@www ~]$ sudo systemctl get-default
multi-user.target
```
*設定圖形啟動
```
[snowFlake@www ~]$ sudo systemctl set-default
graphical.target
```
*忘記指令可以查看/etc/inittab 檔案
```
# cat /etc/inittab
# inittab is no longer used when using systemd.
#
# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
#
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
#
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
#
# To view current default target, run:
# systemctl get-default
#
# To set a default target, run:
# systemctl set-default TARGET.target
#
```