Ubuntu 中查询软件的方法
dpkg查询deb安装的软件
Dpkg 使用文本文件来作为数据库.通称在 
/var/lib/dpkg 目录下. 通称在 status 文件中存储软件状态,和控制信息. 在 info/ 目录下备份控制文件, 并在其下的 .list 文件中记录安装文件清单, 其下的 .mdasums 保存文件的 MD5 编码.dpkg -ldpkg -l firefox* # 会解释状态符号
查询系统中属于nano的文件: 
查看某个文件的归属包:
$ dpkg --listfiles nano查看软件nano的详细信息:
$ dpkg -s nano
查看某个文件的归属包:
$ dpkg -S nano
apt 管理(apt-get)软件:
apt command [options] command
Basic commands: 
list - list packages based on package names
search - search in package descriptions
show - show package details
update - update list of available packages
install - install packages
remove - remove packages
upgrade - upgrade the system by installing/upgrading packages
full-upgrade - upgrade the system by removing/installing/upgrading packages
                        list - list packages based on package names
search - search in package descriptions
show - show package details
update - update list of available packages
install - install packages
remove - remove packages
upgrade - upgrade the system by installing/upgrading packages
full-upgrade - upgrade the system by removing/installing/upgrading packages