如何查看Debian/Ubuntu Linux是否安装了某个软件包？

列出系统上的所有已安装的软件包：

# dpkg -l

是否安装了hello软件包

# dpkg -l hello
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/Name              Version       Architecture  Description
+++-=================-=============-=============-========================================
ii  hello             2.9-2+deb8u1  amd64         example package based on GNU hello

如果我们不知道完整的软件包名称，可以使用通配符 *

# dpkg -l 'h*'
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/Name              Version       Architecture  Description
+++-=================-=============-=============-========================================
ii  hello             2.9-2+deb8u1  amd64         example package based on GNU hello
un  hello-debhelper                   (no description available)
un  hello-traditional                 (no description available)
un  hoogle                            (no description available)
un  hostapd                           (no description available)
ii  hostname          3.15          amd64         utility to set/show the host name or dom
un  hurd                              (no description available)

可以看到还列出了卸载的UN软件包。

要值列出已安装的包，我们可以将输出结果进行grep过滤

# dpkg -l 'h*' | grep ^ii
ii  hello             2.9-2+deb8u1 amd64        example package based on GNU hello
ii  hostname          3.15         amd64        utility to set/show the host name or domain name

还有一种方法是使用-s选项

# dpkg -s hello