使用yum安装dovecot包并查询该包的描述。

1. 使用yum安装dovecot包：

sudo yum install dovecot

2. 查询该包的描述：

yum info dovecot

输出信息如下：

Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: mirrors.tuna.tsinghua.edu.cn
 * extras: mirrors.tuna.tsinghua.edu.cn
 * updates: mirrors.tuna.tsinghua.edu.cn
Installed Packages
Name        : dovecot
Arch        : x86_64
Version     : 2.2.36.1
Release     : 6.el7
Size        : 12 M
Repo        : installed
From repo   : base
Summary     : Secure imap and pop3 server
URL         : http://www.dovecot.org/
License     : MIT and LGPLv2 and BSD
Description : Dovecot is an IMAP server for Linux/UNIX-like systems, written with security
            : primarily in mind. It also contains a small POP3 server. It supports mail in
            : either of maildir or mbox formats.

可以看到，dovecot是一个安全的IMAP和POP3服务器，支持maildir或mbox格式的电子邮件。