Linux下SSH安装、更新及XShell连接

本文以Ubuntu为例进行说明

ssh程序分为有客户端程序openssh-client和服务端程序openssh-server。如果需要ssh登陆到别的电脑，需要安装openssh-client，该程序ubuntu是默认安装的。而如果需要从远程连接到本机，则需要安装openssh-server，该程序需要自己安装。在Ubuntu下安装openssh-server非常简单。

首先，我们确认ssh服务是否已经安装。

（1）输入：ps -e|grep ssh，如果服务已经启动，则可以同时看到‘ssh-agent’和‘sshd’。

a）如果只看到‘ssh-agent’则表示服务没有启动，需要启动，输入：/etc/init.d/ssh start,如果输入之后无反应或返回一些错误信息，则表示ssh服务没有安装，需要安装openssh-server。转入（2）

b)如果同时看到‘ssh-agent’和‘sshd’，则表示服务正常，已启动。

（2）输入：sudo apt-get install openssh-server，安装服务

如果出现

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.

等一些错误信息，则表示你需要更新apt-get，命令：sudo
apt-get update,当然此时你也许会碰到无法更新，因为国内网络限制，进行官方更新总会出各种问题，更新失败时，你可以采用替换更新源的方法。步骤如下

1）先备份下系统原来的原地址列表文件，命令：sudo cp /etc/apt/sources.list /etc/apt/sources.list.old

2)然后对该文件进行修改，命令：sudo gedit/etc/apt/sources.list

可以在里面添加资源地址，也可以直接覆盖掉原来的。

以下有一些比较好的源，大家看情况添加两三个即可。

#网易的源（163源，无论是不是教育网，速度都很快）

deb http://mirrors.163.com/ubuntu/ raring main universe restricted multiverse

deb-src http://mirrors.163.com/ubuntu/ raring main universe restricted multiverse

deb http://mirrors.163.com/ubuntu/ raring-security universe main multiverse restricted

deb-src http://mirrors.163.com/ubuntu/ raring-security universe main multiverse restricted

deb http://mirrors.163.com/ubuntu/ raring-updates universe main multiverse restricted

deb http://mirrors.163.com/ubuntu/ raring-proposed universe main multiverse restricted

deb-src http://mirrors.163.com/ubuntu/ raring-proposed universe main multiverse restricted

deb http://mirrors.163.com/ubuntu/ raring-backports universe main multiverse restricted

deb-src http://mirrors.163.com/ubuntu/ raring-backports universe main multiverse restricted

deb-src http://mirrors.163.com/ubuntu/ raring-updates universe main multiverse restricted

#搜狐的源（sohu 源今天还没有更新，不过应该快了）

deb http://mirrors.sohu.com/ubuntu/ raring main restricted

deb-src http://mirrors.sohu.com/ubuntu/ raring main restricted

deb http://mirrors.sohu.com/ubuntu/ raring-updates main restricted

deb-src http://mirrors.sohu.com/ubuntu/ raring-updates main restricted

deb http://mirrors.sohu.com/ubuntu/ raring universe

deb-src http://mirrors.sohu.com/ubuntu/ raring universe

deb http://mirrors.sohu.com/ubuntu/ raring-updates universe

deb-src http://mirrors.sohu.com/ubuntu/ raring-updates universe

deb http://mirrors.sohu.com/ubuntu/ raring multiverse

deb-src http://mirrors.sohu.com/ubuntu/ raring multiverse

deb http://mirrors.sohu.com/ubuntu/ raring-updates multiverse

deb-src http://mirrors.sohu.com/ubuntu/ raring-updates multiverse

deb http://mirrors.sohu.com/ubuntu/ raring-backports main restricted universe multiverse

deb-src http://mirrors.sohu.com/ubuntu/ raring-backports main restricted universe multiverse

deb http://mirrors.sohu.com/ubuntu/ raring-security main restricted

deb-src http://mirrors.sohu.com/ubuntu/ raring-security main restricted

deb http://mirrors.sohu.com/ubuntu/ raring-security universe

deb-src http://mirrors.sohu.com/ubuntu/ raring-security universe

deb http://mirrors.sohu.com/ubuntu/ raring-security multiverse

deb-src http://mirrors.sohu.com/ubuntu/ raring-security multiverse

deb http://extras.ubuntu.com/ubuntu raring main

deb-src http://extras.ubuntu.com/ubuntu raring main

#台湾源（台湾的ubuntu 更新源还是很给力的）

deb http://tw.archive.ubuntu.com/ubuntu/ raring main universe restricted multiverse

deb-src http://tw.archive.ubuntu.com/ubuntu/ raring main universe restricted multiverse

deb http://tw.archive.ubuntu.com/ubuntu/ raring-security universe main multiverse restricted

deb-src http://tw.archive.ubuntu.com/ubuntu/ raring-security universe main multiverse restricted

deb http://tw.archive.ubuntu.com/ubuntu/ raring-updates universe main multiverse restricted

deb-src http://tw.archive.ubuntu.com/ubuntu/ raring-updates universe main multiverse restricted

#骨头源，骨头源是bones7456架设的一个Ubuntu源 ，提供ubuntu,deepin

deb http://ubuntu.srt.cn/ubuntu/ raring main universe restricted multiverse

deb-src http://ubuntu.srt.cn/ubuntu/ raring main universe restricted multiverse

deb http://ubuntu.srt.cn/ubuntu/ raring-security universe main multiverse restricted

deb-src http://ubuntu.srt.cn/ubuntu/ raring-security universe main multiverse restricted

deb http://ubuntu.srt.cn/ubuntu/ raring-updates universe main multiverse restricted

deb http://ubuntu.srt.cn/ubuntu/ raring-proposed universe main multiverse restricted

deb-src http://ubuntu.srt.cn/ubuntu/ raring-proposed universe main multiverse restricted

deb http://ubuntu.srt.cn/ubuntu/ raring-backports universe main multiverse restricted

deb-src http://ubuntu.srt.cn/ubuntu/ raring-backports universe main multiverse restricted

deb-src http://ubuntu.srt.cn/ubuntu/ raring-updates universe main multiverse restricted

#ubuntu.cn99.com源（推荐）:

deb http://ubuntu.cn99.com/ubuntu/ raring main restricted universe multiverse

deb http://ubuntu.cn99.com/ubuntu/ raring-updates main restricted universe multiverse

deb http://ubuntu.cn99.com/ubuntu/ raring-security main restricted universe multiverse

deb http://ubuntu.cn99.com/ubuntu/ raring-backports main restricted universe multiverse

deb http://ubuntu.cn99.com/ubuntu-cn/ raring main restricted universe multiverse

#教育网源

#电子科技大学

deb http://ubuntu.uestc.edu.cn/ubuntu/ raring main restricted universe multiverse

deb http://ubuntu.uestc.edu.cn/ubuntu/ raring-backports main restricted universe multiverse

deb http://ubuntu.uestc.edu.cn/ubuntu/ raring-proposed main restricted universe multiverse

deb http://ubuntu.uestc.edu.cn/ubuntu/ raring-security main restricted universe multiverse

deb http://ubuntu.uestc.edu.cn/ubuntu/ raring-updates main restricted universe multiverse

deb-src http://ubuntu.uestc.edu.cn/ubuntu/ raring main restricted universe multiverse

deb-src http://ubuntu.uestc.edu.cn/ubuntu/ raring-backports main restricted universe multiverse

deb-src http://ubuntu.uestc.edu.cn/ubuntu/ raring-proposed main restricted universe multiverse

deb-src http://ubuntu.uestc.edu.cn/ubuntu/ raring-security main restricted universe multiverse

deb-src http://ubuntu.uestc.edu.cn/ubuntu/ raring-updates main restricted universe multiverse

#中国科技大学

deb http://debian.ustc.edu.cn/ubuntu/ raring main restricted universe multiverse

deb http://debian.ustc.edu.cn/ubuntu/ raring-backports restricted universe multiverse

deb http://debian.ustc.edu.cn/ubuntu/ raring-proposed main restricted universe multiverse

deb http://debian.ustc.edu.cn/ubuntu/ raring-security main restricted universe multiverse

deb http://debian.ustc.edu.cn/ubuntu/ raring-updates main restricted universe multiverse

deb-src http://debian.ustc.edu.cn/ubuntu/ raring main restricted universe multiverse

deb-src http://debian.ustc.edu.cn/ubuntu/ raring-backports main restricted universe multiverse

deb-src http://debian.ustc.edu.cn/ubuntu/ raring-proposed main restricted universe multiverse

deb-src http://debian.ustc.edu.cn/ubuntu/ raring-security main restricted universe multiverse

deb-src http://debian.ustc.edu.cn/ubuntu/ raring-updates main restricted universe multiverse

#北京理工大学

deb http://mirror.bjtu.edu.cn/ubuntu/ raring main multiverse restricted universe

deb http://mirror.bjtu.edu.cn/ubuntu/ raring-backports main multiverse restricted universe

deb http://mirror.bjtu.edu.cn/ubuntu/ raring-proposed main multiverse restricted universe

deb http://mirror.bjtu.edu.cn/ubuntu/ raring-security main multiverse restricted universe

deb http://mirror.bjtu.edu.cn/ubuntu/ raring-updates main multiverse restricted universe

deb-src http://mirror.bjtu.edu.cn/ubuntu/ raring main multiverse restricted universe

deb-src http://mirror.bjtu.edu.cn/ubuntu/ raring-backports main multiverse restricted universe

deb-src http://mirror.bjtu.edu.cn/ubuntu/ raring-proposed main multiverse restricted universe

deb-src http://mirror.bjtu.edu.cn/ubuntu/ raring-security main multiverse restricted universe

deb-src http://mirror.bjtu.edu.cn/ubuntu/ raring-updates main multiverse restricted universe

#兰州大学

deb ftp://mirror.lzu.edu.cn/ubuntu/ raring main multiverse restricted universe

deb ftp://mirror.lzu.edu.cn/ubuntu/ raring-backports main multiverse restricted universe

deb ftp://mirror.lzu.edu.cn/ubuntu/ raring-proposed main multiverse restricted universe

deb ftp://mirror.lzu.edu.cn/ubuntu/ raring-security main multiverse restricted universe

deb ftp://mirror.lzu.edu.cn/ubuntu/ raring-updates main multiverse restricted universe

deb ftp://mirror.lzu.edu.cn/ubuntu-cn/ raring main multiverse restricted universe

#上海交通大学（上海交大源，教育网的速度不用说了）

deb http://ftp.sjtu.edu.cn/ubuntu/ raring main multiverse restricted universe

deb http://ftp.sjtu.edu.cn/ubuntu/ raring-backports main multiverse restricted universe

deb http://ftp.sjtu.edu.cn/ubuntu/ raring-proposed main multiverse restricted universe

deb http://ftp.sjtu.edu.cn/ubuntu/ raring-security main multiverse restricted universe

deb http://ftp.sjtu.edu.cn/ubuntu/ raring-updates main multiverse restricted universe

deb http://ftp.sjtu.edu.cn/ubuntu-cn/ raring main multiverse restricted universe

deb-src http://ftp.sjtu.edu.cn/ubuntu/ raring main multiverse restricted universe

deb-src http://ftp.sjtu.edu.cn/ubuntu/ raring-backports main multiverse restricted universe

deb-src http://ftp.sjtu.edu.cn/ubuntu/ raring-proposed main multiverse restricted universe

deb-src http://ftp.sjtu.edu.cn/ubuntu/ raring-security main multiverse restricted universe

deb-src http://ftp.sjtu.edu.cn/ubuntu/ raring-updates main multiverse restricted universe
添加好后保存，再输入sudo apt-get update就可以更新了，慢慢等待下载吧。
（3）更新完之后，重新输入sudo apt-get install openssh-server进行安装，然后再输入ps
-e|grep ssh检查是否启动。

（4）启动、停止和重启openssh-server命令如下

/etc/init.d/ssh start

/etc/init.d/ssh stop

/etc/init.d/ssh restart

（5）配置openssh-server

openssh-server配置文件位于/etc/ssh/sshd_config，在这里可以配置SSH的服务端口等，例如：默认端口是22，可以自定义为其他端口号，如222，然后需要重启SSH服务。

（6）Ubuntu中配置openssh-server开机自动启动

打开/etc/rc.local文件，在exit 0语句前加入：

/etc/init.d/ssh start

附带一些基本命令，留存备用，伤不起的不经常使用Linux，忘得好快。

（1）Linux系统一般默认user用户，此时要切换到root用户时，命令：sudo su，默认时Ubuntu的root用户是没有固定密码，密码随机产生并动态改变，不可直接用su（switch
user）来切换

（2）root用户切换回user用户,命令：su user(user即你的用户名)，或直接输入exit或ctrl+D

（3）给root设定一个密码，命令：sudo passwd root，然后按提示来，此时即可利用su
root，切换root用户，或者sudo su

重启命令：

1、reboot

2、shutdown -r now 立刻重启(root用户使用)

3、shutdown -r 10 过10分钟自动重启(root用户使用)

4、shutdown -r 20:35 在时间为20:35时候重启(root用户使用)

如果是通过shutdown命令设置重启的话，可以用shutdown -c命令取消重启

关机命令：

1、halt 立刻关机

2、poweroff 立刻关机

3、shutdown -h now 立刻关机(root用户使用)

4、shutdown -h 10 10分钟后自动关机

如果是通过shutdown命令设置关机的话，可以用shutdown -c命令取消重启