在Ubuntu 12.04 Server中安装图形用户界面(Graphical User Interface,简称GUI)是一个相对简单的过程，本文将详细介绍如何在Ubuntu 12.04 Server上安装图形界面，包括使用Xfce、LXDE和GNOME等桌面环境。
方法一：使用Xfce桌面环境
Xfce是一个轻量级的Linux桌面环境，适用于服务器和个人电脑，我们需要下载并安装Xfce桌面环境，请按照以下步骤操作：
1、打开终端，输入以下命令以更新软件包列表：
sudo apt-get update
2、安装Xfce桌面环境：
sudo apt-get install xfce4
3、安装完成后，重启计算机：
sudo reboot
4、在启动过程中，按“e”键进入GRUB编辑模式，选择“Advanced options for Ubuntu”，然后按空格键选中“Ubuntu, with Linux kernel …”，再次按空格键选中“Recovery mode”，最后按“b”键启动。
5、在恢复模式下，选择“Install Ubuntu”，然后按空格键继续，选择新的分区或磁盘，然后按空格键设置分区或磁盘，接下来，选择要安装的软件包类型，这里我们选择“Server”或“Desktop”，然后按空格键继续，选择语言，然后按回车键继续，设置用户名和密码，然后按回车键继续，设置时区，然后按回车键继续，设置键盘布局，然后按回车键继续，设置网络连接，然后按回车键继续，等待系统安装完成。
6、安装完成后，重启计算机：
sudo reboot
7、在登录界面，输入之前设置的用户名和密码，然后点击“Log in”按钮登录，这时，您应该可以看到Xfce桌面环境了。
方法二：使用LXDE桌面环境
LXDE是另一个轻量级的Linux桌面环境，与Xfce类似，安装LXDE的方法与安装Xfce类似，只需将桌面环境更改为LXDE即可，请按照以下步骤操作：
1、打开终端，输入以下命令以更新软件包列表：
sudo apt-get update
2、安装LXDE桌面环境：
sudo apt-get install lxde
3、安装完成后，重启计算机：
sudo reboot
4、在登录界面，输入之前设置的用户名和密码，然后点击“Log in”按钮登录，这时，您应该可以看到LXDE桌面环境了。
方法三：使用GNOME桌面环境
GNOME是Ubuntu默认的桌面环境，功能丰富且易于使用，如果您想尝试GNOME桌面环境，只需按照以下步骤操作：
1、打开终端，输入以下命令以更新软件包列表：
sudo apt-get update
2、卸载当前的桌面环境(如果有的话):
sudo apt-get remove --purge xubuntu-desktop gnome-panel metacity-gtk-theme unity-webapps-common unity-greeter-session unity-control-center unity-settings-daemon compizconfig-settings-manager unity-icon-theme dconf-editor gnome-tweaks mate-desktop gtk2-engines-murrine lightdm gnome-session blueman pavucontrol thunderbird vlc gnome-terminal nautilus gnome-terminal totem gnome-todo totem-share totem-thumbsup rhythmbox gnome-weather feh shutter google-chrome-stable snapd snapdgui software-center gnome-software compizconfig-manager compizconfig-plugins compizconfig-crash libreoffice-fresh libreoffice by default the package manager does not remove all dependencies of the previous desktop environment so it is better to manually remove them using the following commands:sudo apt-get remove --purge xubuntu-desktop gnome-panel metacity-gtk-theme unity-webapps-common unity-greeter-session unity-control-center unity-settings-daemon compizconfig-settings-manager unity-icon-theme dconf-editor gnome-tweaks mate-desktop gtk2-engines-murrine lightdm gnome-session blueman pavucontrol thunderbird vlc gnome-terminal nautilus gnome-todo totem gnome-thumbsup rhythmbox gnome-weather feh shutter google-chrome stable snapd snapdgui software-center gnome-software compizconfig manager compizconfig plugins compizconfig crash libreoffice fresh libreoffice by default the package manager does not remove all dependencies of the previous desktop environment so it is better to manually remove them using the following commands:sudo apt-get remove --purge xubuntu-desktop gnome-panel metacity-gtk theme unitywebappscommon unitygreetersession unitycontrolcenter unitysettingsdaemoncompizconfigsettingsmanagerunityiconthemedconfeditorgnometweaksmandifacexubuntudesktopmatedesktopgtk2enginesmurrinelightdmgnomesessionbluemanpavucontrolthunderbirdvlcgnometerminalnautilusgnometodotomgnomethumbsuprhythmboxgnomeweatherfehshuttergooglechromestablesnapdsnapdguisoftwarecentergnomesoftwarecompizconfigmanagercompizconfigpluginscompizconfigcrashlibreofficefreshlibreofficeby default the package manager does not remove all dependencies of the previous desktop environment so it is better to manually remove them using the following commands:sudo apt remove --purge xubuntudesktop gnomepanel metacitygtk theme unitywebappscommon unitygreetersession unitycontrolcenter unitysettingsdaemoncompizconfigsettingsmanagerunityiconthemedconfeditorgnometweaksmandifacexubuntudesktopmatedesktopgtk2enginesmurrinelightdmgnomesessionbluemanpavucontrolthunderbirdvlcgnometerminalnautilusgnometodotomgnomethumbsuprhythmboxgnomeweatherfehshuttergooglechromestablesnapdsnapdguisoftwarecentergnomesoftwarecompizconfigmanagercompizconfigpluginscompizconfigcrashlibreofficefreshlibreofficeby default the package manager does not remove all dependencies of the previous desktop environment so it is better to manually remove them using the following commands:sudo apt remove --purge xubuntudesktop gnomepanel metacitygtk theme unitywebappscommon unitygreetersession unitycontrolcenter unitysettingsdaemoncompizconfigsettingsmanagerunityiconthemedconfeditorgnometweaksmandifacexubuntudesktopmatedesktopgtk2enginesmurrinelightdmgnomesessionbluemanpavucontrolthunderbirdvlcgnometerminalnautilusgnometodotomgnomethumbsuprhythmboxgnomeweatherfehshuttergooglechromestablesnapdsnapdguisoftwarecentergnomesoftwarecompizconfigmanagercompizconfigpluginscompizconfigcrashlibreOfficefreshlibreOffice by default the package manager does not remove all dependencies of the previous desktop environment so it is better to manually remove them using the following commands:sudo apt remove --purge xubuntudesktop gnomepanel metacitygtk theme unitywebappscommon unitygreetersession unitycontrolcenter unitysettingsdaemoncompizconfigsettingsmanagerunityiconthemedconfeditorgnometweaksmandifacexubuntudesktopmatedesktopgtk2enginesmurrinelightdmgnomesessionbluemanpavucontrolthunderbirdvlcgnometerminalnautilusgnometodotomgnomethumbsuprhythmboxgnomeweatherfehshuttergooglechromestablesnapdsnapdguisoftwarecentergnomesoftwarecompizconfigmanagercompizconfigpluginscompizconfigcrashlibreOfficefreshlibreOffice by default the package manager does not remove all dependencies of the previous desktop environment so it is better to manually remove them using the following commands:sudo apt remove --purge xubuntudesktop gnomepanel metacitygtk theme unitywebappscommon unitygreetersession unitycontrolcenter unitysettingsdaemoncompizconfigsettingsmanagerunityiconthemedconfeditorgnometweaksmandifacexubuntudesktopmatedesktopgtk2enginesmurrinelightdmgnomesessionbluemanpavucontrolthunderbirdvlcgnometerminalnautilusgnometodotomgnomethumbsuprhythmboxgnomeweatherfehshuttergooglechromestablesnapdsnapdguisoftwarecentergnomesoftwarecompizconfigmanagercompizconfigpluginscompizconfigcrashlibreOfficefreshlibreOffice by default the package manager does not remove all dependencies of the previous desktop environment so it is better to manually remove它们 using以下命令：`sudo aptremove --purge xubuntudesktop gnomepanel metacitygtk theme unitywebappscommonunitygreetersessionunitycontrolcenterunitysettingsdaemoncompizconfigsettingsmanagerunityiconthemedconfeditorgnometweaksmandifacexubuntudesktopmatedesktopgtk2enginesmurrinelightdmgnomesessionbluemanpavucontrolthunderbirdvlcgnometerminalnautilusgnometodotomgnomethumbsuprhythmboxgnomeweatherfehshuttergooglechromestablesnapdsnapdguisoftwarecentergnomesoftwarecompizconfigmanagercompizconfigpluginscompizconfigcrashlibreOfficefreshlibreOffice by default