使用命令passwd修改密码时，遇到如下问题：
# echo 'utf8'| passwd zhangsan --stdin
Changing password for user zhangsan.
passwd: Have exhausted maximum number of retries for service
可以尝试改用密码 chpasswd修改zhangsan的密码：
echo 'zhangsan:utf8' |chpasswd
有可能就可以了
# echo 'utf8'| passwd zhangsan --stdin
Changing password for user zhangsan.
passwd: Have exhausted maximum number of retries for service
可以尝试改用密码 chpasswd修改zhangsan的密码：
echo 'zhangsan:utf8' |chpasswd
有可能就可以了
