apt-* 查看，安装，删除，更新包。
1. apt-cache search: Search Repository Using Package Name
apt-cache search ^包名$
在Repo中查找包名，以查找Apache 2为例
$ apt-cache search ^apache2$
apache2 - Apache HTTP Server metapackage
2. apt-cache search: Search Repository Using Package Description
apt-cache search + 包描述, 有时不知道包的准备名字，可以通过包的描述信息查找。
$ apt-cache search "Apache HTTP Server"
apache2 - Apache HTTP Server metapackage
apache2-doc - Apache HTTP Server documentation
apache2-mpm-event - Apache HTTP Server - event driven model
apache2-mpm-prefork - Apache HTTP Server - traditional non-threaded model
apache2-mpm-worker - Apache HTTP Server - high speed threaded model
apache2.2-common - Apache HTTP Server common files
3. apt-file search: Search Repository Using a Filename from the Package
apt-file search + 包中的任意文件名， 有时只知道包里的配置相关文件或可能执行文件，也可以通过这些信息查找包。
$ apt-file search apache2.conf
apache2.2-common: /etc/apache2/apache2.conf
apache2.2-common: /usr/share/doc/apache2.2-common/examples/apache2/apache2.conf.gz
4. apt-cache show: Basic Information About a Package
apt-cache show + 包， 显示包的基本信息。
$ apt-cache show apache2
Package: apache2
Priority: optional
Maintainer: Ubuntu Core Developers
Original-Maintainer: Debian Apache Maintainers
Version: 2.2.11-2ubuntu2.3
Depends: apache2-mpm-worker (>= 2.2.11-2ubuntu2.3)
| apache2-mpm-prefork (>= 2.2.11-2ubuntu2.3)
| apache2-mpm-event (>= 2.2.11-2ubuntu2.3)
Filename: pool/main/a/apache2/apache2_2.2.11-2ubuntu2.3_all.deb
Size: 46350
Description: Apache HTTP Server metapackage
The Apache Software Foundation's goal is to build a secure, efficient and
extensible HTTP server as standards-compliant open source software.
Homepage: http://httpd.apache.org/
5. apt-cache showpkg: Detailed Information About a Package
apt-cache showdpkg + 包，显示包更加祥细的信息。
$ apt-cache showpkg apache2
Package: apache2
Versions:
2.2.11-2ubuntu2.3 (/var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_jaunty-updates_main_binary-i386_Packages) (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_jaunty-security_main_binary-i386_Packages)
Description Language:
File: /var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_jaunty-updates_main_binary-i386_Packages
MD5: d24f049cd70ccfc178dd8974e4b1ed01
Reverse Depends:
squirrelmail,apache2
squid3-cgi,apache2
phpmyadmin,apache2
ipplan,apache2
Dependencies:
2.2.11-2ubuntu2.3 - apache2-mpm-worker (18 2.2.11-2ubuntu2.3) apache2-mpm-prefork (18 2.2.11-2ubuntu2.3) apache2-mpm-event (2 2.2.11-2ubuntu2.3)
2.2.11-2ubuntu2 - apache2-mpm-worker (18 2.2.11-2ubuntu2) apache2-mpm-prefork (18 2.2.11-2ubuntu2) apache2-mpm-event (2 2.2.11-2ubuntu2)
Provides:
2.2.11-2ubuntu2.3 -
2.2.11-2ubuntu2 -
Reverse Provides:
apache2-mpm-itk 2.2.6-02-1build4.3
apache2-mpm-worker 2.2.11-2ubuntu2.3
apache2-mpm-prefork 2.2.11-2ubuntu2.3
apache2-mpm-prefork 2.2.11-2ubuntu2
apache2-mpm-event 2.2.11-2ubuntu2
6. apt-file list: List all the Files Located Inside a Package
apt-file list + 包，显示包内所有文件。
$ apt-file list apache2 | more
apache2: /usr/share/bug/apache2/control
apache2: /usr/share/bug/apache2/script
apache2: /usr/share/doc/apache2/NEWS.Debian.gz
apache2: /usr/share/doc/apache2/README.Debian.gz
apache2: /usr/share/doc/apache2/changelog.Debian.gz
...
7.apt-cache depends: List all Dependent Packages
apt-cache depends + 包， 显示包的所有依赖。在安装包前需要检查安装包所有的依赖
$ apt-cache depends apache2
apache2
|Depends: apache2-mpm-worker
|Depends: apache2-mpm-prefork
Depends: apache2-mpm-event
8. dpkg -l: Is the Package Already Installed?
dpkg -l , 显示系统中所有的安装包
9. apt-get install: Install a Package
apt-get install + 包，安装包。
10. apt-get remove: Delete a Package
apt-get remove/purge , 删除包
apt-get remove will not delete the configuration files of the package
apt-get purge will delete the configuration files of the package
11. apt-get -u install: Upgrade a Specific Package
apt-get -u install + 包，更新安装包。
12. apt-get -u upgrade: Upgrade all Packages
更新所有安装包。