一、服务器安装软件是出现以下的错误信息：

www@TinywanAliYun:~$ sudo apt-get install letsencrypt
Reading package lists... Done
Building dependency tree       
Reading state information... Done
letsencrypt is already the newest version (0.17.0-2+ubuntu16.04.1+certbot+1).
0 upgraded, 0 newly installed, 0 to remove and 52 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up php7.0-mysql (7.0.22-0ubuntu0.16.04.1) ...
dpkg: error processing package php7.0-mysql (--configure):
 subprocess installed post-installation script returned error exit status 10
Errors were encountered while processing:
 php7.0-mysql
E: Sub-process /usr/bin/dpkg returned an error code (1)

二、具体步骤

1、将info文件夹更名

命令如下：www@TinywanAliYun:~# mv /var/lib/dpkg/info/ /var/lib/dpkg/info_old/

2、再新建一个新的info文件夹 

命令如下：www@TinywanAliYun:~# mkdir /var/lib/dpkg/info/

3、更新文件列表：apt-get update

命令如下：www@TinywanAliYun:~# apt-get update

信息如下：       

www@TinywanAliYun:~$ sudo apt update
[sudo] password for www: 
Hit:1 http://mirrors.cloud.aliyuncs.com/ubuntu xenial InRelease
Hit:2 http://mirrors.cloud.aliyuncs.com/ubuntu xenial-updates InRelease                                                                 
Hit:3 http://mirrors.cloud.aliyuncs.com/ubuntu xenial-security InRelease                                                                
Hit:4 http://ppa.launchpad.net/certbot/certbot/ubuntu xenial InRelease 

4、重新安装 

命令如下：www@TinywanAliYun:~# apt-get -f install

信息如下：

www@TinywanAliYun:~$ sudo  apt-get -f install
Reading package lists... Done
Building dependency tree       
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 52 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Setting up php7.0-mysql (7.0.22-0ubuntu0.16.04.1) ...

5、执行完上一步操作后会在新的info文件夹下生成一些文件，现将这些文件全部移到info_old文件夹下 

命令如下：www@TinywanAliYunu:~# mv /var/lib/dpkg/info/* /var/lib/dpkg/info_old/

6、把自己新建的info文件夹删掉 

命令如下：www@TinywanAliYun:~# rm -rf /var/lib/dpkg/info

7、把info_old文件夹重新改回info 

命令如下：www@TinywanAliYun:~# mv /var/lib/dpkg/info_old/ /var/lib/dpkg/info/

8、输入上述命令之后。

 在执行 sudo apt-get update 就不会有问题了

9、继续到第一步的安装信息

www@TinywanAliYun:~$ sudo apt-get install letsencrypt
Reading package lists... Done
Building dependency tree       
Reading state information... Done
letsencrypt is already the newest version (0.17.0-2+ubuntu16.04.1+certbot+1).
0 upgraded, 0 newly installed, 0 to remove and 52 not upgraded.

 10、安装结束