ssh without password

使用ssh協定,要登入遠方主機或拷貝遠方檔案時,有免去輸入帳密方法,如下:
  原理:  將自己的公開金鑰(localhost:~/.ssh/*.pub)加入
        遠方主機的授權金鑰檔內(remotehost:~/.ssh/authorized_keys)

  工具:  可利用以下reg_ssh_key.sh批次檔作登入及加入動作.
        以後,利用終端機ssh remotehost或scp file remotehost:時,就可以免問帳密.

  方法:  localhost> vi reg_ssh_key.sh    # 建立註冊批次檔,user為遠端主機帳號
          cat ~/.ssh/*.pub | ssh user@$* "cat >> .ssh/authorized_keys"

        localhost> sh reg_ssh_key.sh remotehost  # 利用註冊批次檔,向遠方主機remotehost註冊
金鑰
        Password:

        localhost> ssh remotehost   # 測試ssh自動登入遠方主機,不問密碼

        remotehost>

註:
1.遠方主機的檔案目錄必需設定權限如下:
  remotehost:~/.ssh                 目錄權限為711,即己/群/他權限分別為rwx/x/x,
  remotehost:~/.ssh/authorized_keys 檔案權限為644,即己/群/他權限分別為rw/r/r,

2.個人金鑰生成法:
  若有ssh-user-config指令,以問答方式產生個人金鑰,
  若無該指令,可用ssh-keygen指令產生

3.本地/遠方所需ssh組態檔如下,
  客戶端: /etc/ssh_config 或 /etc/ssh/ssh_config
  伺服端: /etc/sshd_config 或 /etc/ssh/sshd_config

------------------  reg_ssh_key.sh ----------------------
#
# http://josephjiang.com/article/understand-ssh-key/
#
#  run to get /etc/ssh_config, /etc/sshd_config
#     ssh-host-config
#  run to get ~/.ssh/identify.pub, id_rsa.pub, id_dsa.pub
#     ssh-user-config
#     #ssh-keygen -t rsa1
#     #ssh-keygen -t rsa
#     #ssh-keygen -t dsa
#  chmod 711 remote:~/.ssh
#  chmod 644 remote:~/.ssh/authorized_keys
#
cat ~/.ssh/*.pub | ssh user@$* "cat >> .ssh/authorized_keys"