最近管理的一批機器，有個需求是要統一修改一個帳號的用戶名密碼，比如將qa帳號的密碼改為1234，后來還為了腳本化，很方便的執行，還使用了非交互式地修改用戶的密碼。簡單記錄一下吧。

1. 交互式配置本地用戶的密碼：passwd 命令

代碼如下:
[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戶的密碼：chpasswd

代碼如下:
# chpasswd命令使用起來很簡潔
[root@host_221-81 ~]# echo "qa:1234" | chpasswd
 
# 使用passwd命令，也可以實現非交互式修改密碼
[root@host_221-81 ~]# echo "1234" | passwd --stdin "qa"
Changing password for user qa.
passwd: all authentication tokens updated successfully.

3. 使用expect來處理交互式輸入，從而實現非交互式的密碼修改。

代碼如下:
#!/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：腳本的第二行，這種寫法可能比較陌生，這是在TCL語言中的語法，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.

該腳本的執行結果為：

代碼如下:
[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.