ssh-copy-id 免密码登录服务器

[techiall]

ssh-copy-id 可以把本地的公钥复制到服务器上，这样子就可以不用密码登录了。

使用方法如下：

$ ssh-copy-id -h
Usage: /usr/bin/ssh-copy-id [-h|-?|-f|-n] [-i [identity_file]] [-p port] [[-o <ssh -o options>] ...] [user@]hostname
        -f: force mode -- copy keys without trying to check if they are already installed
        -n: dry run    -- no keys are actually copied
        -h|-?: print this help

基本使用

假设服务器的用户名为 root，地址为 192.168.1.1

如果你本地没有 id_rsa.pub 文件的话，需要先用 ssh-keygen 命令生成公钥和私钥。

不指定参数执行

ssh-copy-id root@192.168.1.1

执行以上命令的时候会让你输入服务器密码，输入完后会提示你添加的条数

/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'root@192.168.1.1'"
and check to make sure that only the key(s) you wanted were added.

如果你重复执行命令的话，会提示你已经添加过了，会出现如下提示，如果你想覆盖，可以使用 -f 参数。

$ ssh-copy-id root@192.168.1.1
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed

/usr/bin/ssh-copy-id: WARNING: All keys were skipped because they already exist on the remote system.
                (if you think this is a mistake, you may want to use -f option)

使用 -n 参数可以模拟命令执行过程，但实际上不会被添加。

指定公钥

ssh-copy-id 和 ssh 命令类似，可以指定 -i 参数，即指定公钥所在位置，使用方法如下

前提还是需要用 ssh-keygen 生成公钥私钥文件，如 ssh-keygen -f demo

ssh-copy-id -i ./demo root@192.168.1.1