Linux下交互式与非交互式修改用户密码的例子

最近管理的一批机器，有个需求是要统一修改一个帐号的用户名密码，比如将qa帐号的密码改为1234，后来还为了脚本化，很方便的执行，还使用了非交互式地修改用户的密码。简单记录一下吧。

1. 交互式配置本地用户的密码：passwd 命令

[root@host_221-81 ~]# passwd qa
changing password for user qa.
new password:
bad password: it is too short
bad password: is too simple
retype new password:
passwd: all authentication tokens updated successfully.

2. 非交互式修改本地用户的密码：chpasswd

# chpasswd命令使用起来很简洁
[root@host_221-81 ~]# echo "qa:1234" | chpasswd
 
# 使用passwd命令，也可以实现非交互式修改密码
[root@host_221-81 ~]# echo "1234" | passwd --stdin "qa"
changing password for user qa.
passwd: all authentication tokens updated successfully.

3. 使用expect来处理交互式输入，从而实现非交互式的密码修改。

#!/bin/sh
# \
exec expect -f "$0" "$@"
if { $argc != 2 } {
    puts "usage: $argv0 <username> <passwd>"
    exit 1
}
set password [lindex $argv 1]
spawn passwd [lindex $argv 0]
sleep 1
expect "assword:"
send "$password\r"
expect "assword:"
send "$password\r"
expect eof

注意：脚本的第二行，这种写法可能比较陌生，这是在tcl语言中的语法，the backslash is recognized as part of a comment to sh, but in tcl the backslash continues the comment into the next line which keeps the exec command from executing again.

该脚本的执行结果为：

[root@smilejay ~]# ./change-pwd-expect.sh qa 1234
spawn passwd qa
changing password for user qa.
new password:
bad password: it is too short
bad password: is too simple
retype new password:
passwd: all authentication tokens updated successfully.