shell脚本编程-例子_使用expect下载ftp文件

expecthi一种能够按照脚本内容设定的方式和交互程序进行“对话”的程序

由于linux中的一些命令不太适合脚本化的自动运行，比如fdisk、telnet、ftp连接下载等，所以就必须使用expect来解决这些场景下的自动化运行问题。

系统默认没有装ftp、expect命令，需要自己先进行yum安装（也可手工安装）

脚本事例（expect.exp）如下：

#!/usr/bin/expect    
set ip [ lindex $argv 0 ]  #脚本的第一个参数，远程主机的IP地址
set file [ lindex $argv 1 ]  #脚本的第二个参数，指定下载的文件名
set timeout 10 #设置超时时间
spawn ftp $ip #执行ftp $ip命令
expect "Name*" #如果出现Name字符
send "anonymous\n"  #则输入anoymous并回车
expect "Password*" #如果出现Password字符
send "\n" #则仅输入回车
expect "fpt>*" #如果出现ftp字符
send "get $file\n" #则发送get $file命令
expect {
#如果返回的字符串含有received则说明下载成功
"*received*" { send_user "Download successful!";send "quit\n" }
#如果返回的字符串中含有Faild则说明下载失败.
"*Failed*" { send_user "Download failed!";send "quit\n"}
}
expect eof

赋予执行权限：chmod 774 ./expect.exp

执行本脚本是可以使用如下语句：

./expect.exp 195.92.253.2 robots.txt

如果你执行成功应该出现如下语句：

[cos@localhost shell]$ ./expect.exp  195.92.253.2 robots.txt
spawn ftp 195.92.253.2
Connected to 195.92.253.2 (195.92.253.2).
220 (vsFTPd 2.3.4)
Name (195.92.253.2:cos): anonymous
331 Please specify the password.
Password:
230-Welcome to ZenIV
230-
230-The software on this site is made available for free without warranty or
230-other right of recourse implied or otherwise. No statement save one in
230-writing by the owner of the system changes this usage agreement. This 
230-software is provided in the United Kingdom for United Kingdom users,
230-any export download is at your own risk and liability.
230-
230-Many parts of this archive are mirrors of other sites. While we try not
230-to mirror any inappropriate material we do not have editorial control over
230-such mirrors and cannot make such a guarantee.
230-
230-There is no other user agreement, should your local law make such an
230-agreement invalid you are prohibited from using this site, and may be
230-committing an offence under the computer misuse act by continuing.
230-
230-By downloading any file from this site you agree to these terms and
230-conditions, disconnect now if you do not.
230-
230-* * * * * * * * * * * * * Transfer Problems ? * * * * * * * * * * * * *
230-*                                                                     *
230-*  If you are having problems accessing this site, then please use    *
230-*  "passive" transfer mode rather than "port" transfer mode.  Thanks. *
230-*                                                                     *
230-*  Note: do **NOT** try using download accelerators like aria2c which *
230-*        make multiple connections, this will likely trigger an       *
230-*        autonatic ban respons which you will have to request to be   *
230-*        removed                                                      *
230-*                                                                     *
230-* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> get robots.txt
local: robots.txt remote: robots.txt
227 Entering Passive Mode (195,92,253,2,70,227).
150 Opening BINARY mode data connection for robots.txt (103 bytes).
226 Transfer complete.
103 bytes received in 0.000627 secs (164.27 Kbytes/sec)
ftp> Download successful!quit
221 Goodbye.

祝你好运。

2015年10月16日00:33:59