linux命令：ssh scp ssh-keygen -t rsa用法

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SSH远程连接命令：

  用法格式：ssh IPADDR 不指定用户则以当前主机登录系统的用户身份去登录远程主机
    ssh USERNAME@IPADDR  通过ssh协议以某用户身份远程登录到某主机
Usage: ssh root@192.168.1.100  以root身份通过ssh协议远程登录到192.168.1.100主机
    ssh -l USERNAME IPADDR 相当于ssh USERNAME@IPADDR登录模式一样
    ssh USERNAME@IPADDR 'COMMOND' 以USERNAME用户在远程主机上执行COMMOND命令。

SCP远程复制命令：
用法格式：scp SRC原文件或目录 DEST目标目录  跟cp命令一样
      -r：目录也复制
      -a：隐藏文件，链接文件都一起复制
  scp USERNAME@IPADDR:/path/to/somefile /path/to/local  从远程主机复制到本地主机来

scp /path/to/local USERNAME@IPADDR:/path/to/somefile  从本地主机复制到远程主机上


ssh-keygen -t rsa  生成密钥

    生成的密钥保存在以下路径
    私钥密钥保存至：~/.ssh/id_rsa  当前生成用户的家目录下
    公钥密钥保存至：~/.ssh/id_rsa.pub
   -f /path/to/KEY_FILE 指定密码保存路径和文件名
   -P 'password'：指定加密私钥的密码

公钥追加保存至远程主机相对应用户的家目录下的~/.ssh/authorized_keys文件或  ~/.ssh/authorized_keys2文件中，一般追加保存至authorized_keys文件中


ssh-copy-id：将公钥传输至远程服务器 ~/.ssh/id_rsa.pub公钥的保存位置

   ssh-copy-id  该命令并不是所有linux版本都支持
       -i ~/.ssh/id_rsa.pub USERNAME@IPADDR

Usage： ssh-copy-id -i ~/.ssh/id_rsa.pub root@172.16.100.1

实例：如何实现通过ssh远程登录主机不需要输入密码认证

    方法一：把生成的公钥追加保存至远端服务器相对应的家目录下的
         ~/.ssh/authorized_keys文件中即可

[iyunv@localhost ~]# ssh-keygen -t rsa   生成密钥
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
/root/.ssh/id_rsa already exists.
Overwrite (y/n)? y
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.  私钥路径
Your public key has been saved in /root/.ssh/id_rsa.pub.  公钥路径
The key fingerprint is:
c6:30:84:08:94:ff:91:58:82:56:25:d4:4b:53:98:e3 root@localhost.localdomain
[iyunv@localhost ~]# ls /root/.ssh/id_rsa
/root/.ssh/id_rsa
[iyunv@localhost ~]# ls /root/.ssh/id_rsa.pub
/root/.ssh/id_rsa.pub
[iyunv@localhost ~]# scp /root/.ssh/id_rsa.pub root@10.109.134.248:/root  首先把本地生成的                             公钥复制到远程主机的家目录中
[iyunv@localhost ~]# ssh root@10.109.134.248   先远程登录到主机
[iyunv@localhost ~]# ls
id_rsa.pub   install.log   install.log.syslog
[iyunv@localhost ~]# mkdir .ssh 远程主机没有.ssh目录需要新建该目录，且目录权限必须为700
[iyunv@localhost ~]# chmod 700 .ssh/  更改权限为700
[iyunv@localhost ~]#cat ~/id_rsa.pub >> ~/.ssh/authorized_keys 追加保存
[iyunv@localhost ~]#exit  退出远程主机后再通过ssh登录后及可不需要输入密码就登录


  方法二：先生成密钥，然后通过命令直接复制至远程主机中

[iyunv@localhost ~]# ssh-keygen -t rsa   生成密钥

Generating public/private rsa key pair.

Enter file in which to save the key (/root/.ssh/id_rsa):

/root/.ssh/id_rsa already exists.

Overwrite (y/n)? y

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /root/.ssh/id_rsa.  私钥路径

Your public key has been saved in /root/.ssh/id_rsa.pub.  公钥路径

The key fingerprint is:

c6:30:84:08:94:ff:91:58:82:56:25:d4:4b:53:98:e3 root@localhost.localdomain

[iyunv@localhost ~]# ls /root/.ssh/id_rsa

/root/.ssh/id_rsa

[iyunv@localhost ~]# ls /root/.ssh/id_rsa.pub

/root/.ssh/id_rsa.pub

[iyunv@localhost ~]# ssh-copy-id -i /root/.ssh/id_rsd.pub root@10.109.134.248
[iyunv@localhost ~]# ssh root@10.109.134.248重新通过ssh登录远端主机后不用输入密码即可登录