三种Shell脚本编程中避免SFTP输入密码的方法

╰半橙微兮° 2022-12-03 08:43 286阅读 0赞

最近编程中用到sftp上传文件，且需要用crontab预设定时上传事件。而sftp不同于ftp，没有提供选项如 -i 可以将密码直接编码进程序。使用sftp指令，会自动请求用户输入密码。

总结一下可以避免sftp输入密码的三种方式：

# 1. lftp方式 #

LFTP是一款非常著名的字符界面的文件传输工具。支持FTP、HTTP、FISH、SFTP、HTTPS和FTPS协议。

#!/bin/sh 
     
    HOST=192.168.107.132 
    USER=huangmr
    PASS=huangmr  
    echo "Starting to sftp..." 
    lftp -u ${USER},${PASS} sftp://${HOST}:22 <<EOF  
    cd /home/huangmr
    mget *.*  
    bye  
    EOF 
     
    echo "done"

# 2. expect方式 #

Expect是一个免费的编程工具语言，用来实现自动和交互式任务进行通信，而无需人的干预。

要使用expect需要预先安装tcl这个东西,然后再安装expect包。

tcl:     [http://prdownloads.sourceforge.net/tcl/tcl8.4.16-src.tar.gz][http_prdownloads.sourceforge.net_tcl_tcl8.4.16-src.tar.gz]

expect:     [http://sourceforge.net/projects/expect/files/Expect/5.45/expect5.45.tar.gz/download][http_sourceforge.net_projects_expect_files_Expect_5.45_expect5.45.tar.gz_download]

#!/usr/local/bin/expect -f  
    #<---insert here your expect program location
    #procedure to attempt connecting; result 0 if OK, 1 elsewhere
     proc connect {passw} {
      expect {
        "(yes/no)?" {send "yes/r";exp_continue} #第一次使用SFTP时候会要求输入yes/no 
        "password:" {send "$passw/r"            #自动输入密码
      expect {
         "sftp*" {        #检测返回sftp>
       return 0
          }  
      }
         }
      }
      # timed out
      return 1
     }
     
     #read the input parameters
     set user [lindex $argv 0]
     set passw [lindex $argv 1]
     set host [lindex $argv 2]
     set location [lindex $argv 3]
     set file1 [lindex $argv 4]
     
     #puts "Am citit:/n";
     #puts "user: $user";
     #puts "passw: $passw";
     #puts "host: $host";
     #puts "location: $location";
     #puts "file1: $file1";
    
     
     #check if all were provided
     if { $user == "" || $passw == "" || $host == "" || $location == "" || $file1 == "" }  {
       puts "Usage: <user> <passw> <host> <location> <file1 to send>/n"
       exit 1
     }
     
     #sftp to specified host and send the files
     spawn sftp $user@$host
     
     set rez [connect $passw]
     if { $rez == 0 } {
       send "cd $location/r"
       set timeout -1
       send "put $file1/r"
       #send "ls -l/r"
       #send "quit/r"
       #send "mkdir testsftp/r"
       send "quit/r"
       expect eof
       exit 0
     }
     puts "/nCMD_ERR: connecting to server: $host!/n"
     exit 1
     0

expect也可以用两种形式调用

1   ./my.exp $usr $pwd $host $local $file

2. 代码中直接插入

expect<<!

...

# 3. (推荐)生成密钥对 #

因为这种方式不用把密钥卸载程序里,所以更安全

第一步：生成密匙对，我用的是rsa的密钥。使用命令 "ssh-keygen -t rsa"

[user1@rh user1]$ ssh-keygen -t rsa
       Generating public/private rsa key pair.
       Enter file in which to save the key (/home/user1/.ssh/id_rsa):
       Created directory '/home/user1/.ssh'.
       Enter passphrase (empty for no passphrase):
       Enter same passphrase again:
       Your identification has been saved in /home/user1/.ssh/id_rsa.
       Your public key has been saved in /home/user1/.ssh/id_rsa.pub.
       The key fingerprint is:
       e0:f0:3b:d3:0a:3d:da:42:01:6a:61:2f:6c:a0:c6:e7user1@rh.test.com
       [user1@rh user1]$

生成的过程中提示输入密钥对保存位置，直接回车，接受默认值就行了。接着会提示输入一个不同于你的password的密码，直接回车，让它空着。  
当然，也可以输入一个。(我比较懒，不想每次都要输入密码。) 这样，密钥对就生成完了。

其中公共密钥保存在 ~/.ssh/id\_rsa.pub  
私有密钥保存在 ~/.ssh/id\_rsa

然后改一下 .ssh 目录的权限，使用命令 "chmod 755 ~/.ssh"  
   \[user1@rh user1\]$ chmod 755 ~/.ssh

之后把这个密钥对中的公共密钥复制到你要访问的机器上去，并保存为

~/.ssh/authorized_keys
       [user1@rh user1]$ scp ~/.ssh/id_rsa.pub rh1:/home/user1/.ssh/authorized_keys 
       
       user1@rh1's password:
       id_rsa.pub                                    100%  228     3.2MB/s   00:00
       [user1@rh user1]$

之这样就大功告成了。之后再用ssh scp sftp 之类的访问那台机器时，就不用输入密码

了，用在script上更是方便。

[http_prdownloads.sourceforge.net_tcl_tcl8.4.16-src.tar.gz]: http://prdownloads.sourceforge.net/tcl/tcl8.4.16-src.tar.gz
[http_sourceforge.net_projects_expect_files_Expect_5.45_expect5.45.tar.gz_download]: http://sourceforge.net/projects/expect/files/Expect/5.45/expect5.45.tar.gz/download