我正在尝试在我的 amd64 Ubuntu 16.04 系统上安装 doxygen 和 libpcl-dev，这两个包都可以在https://packages.ubuntu.com/xenial/
aptitude 和 synaptic 等其他软件包也出现了同样的问题。我主要尝试使用如下命令来解决此问题；
sudo apt-get install doxygen
输出为；
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package doxygen is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'doxygen' has no installation candidate
我看到其他答案告诉我按 alt-F2 -> software-properties-gtk 并确保在“Ubuntu 软件”选项卡中选中 5 个框，然后执行；
sudo apt-get update
但这给出了相同的结果。
这是我的 sources.list，我想其中可能会有一些东西。
谢谢你的帮助！
###### Ubuntu Main Repos
deb http://archive.ubuntu.com/ubuntu xenial main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu xenial main restricted universe multiverse #Added by software-properties
###### Ubuntu Update Repos
deb http://archive.ubuntu.com/ubuntu xenial-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu xenial-security main restricted universe multiverse #Added by software-properties
deb http://archive.ubuntu.com/ubuntu xenial-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu xenial-updates main restricted universe multiverse #Added by software-properties
编辑：
sudo apt update
给出响应：
[sudo] password for doug:
Get:1 file:/var/cuda-repo-9-0-local InRelease
Ign:1 file:/var/cuda-repo-9-0-local InRelease
Get:2 file:/var/visionworks-repo InRelease
Ign:2 file:/var/visionworks-repo InRelease
Get:3 file:/var/visionworks-sfm-repo InRelease
Ign:3 file:/var/visionworks-sfm-repo InRelease
Get:4 file:/var/visionworks-tracking-repo InRelease
Ign:4 file:/var/visionworks-tracking-repo InRelease
Get:5 file:/var/cuda-repo-9-0-local Release [574 B]
Get:6 file:/var/visionworks-repo Release [1,999 B]
Get:5 file:/var/cuda-repo-9-0-local Release [574 B]
Get:7 file:/var/visionworks-sfm-repo Release [2,003 B]
Get:6 file:/var/visionworks-repo Release [1,999 B]
Get:8 file:/var/visionworks-tracking-repo Release [2,008 B]
Get:7 file:/var/visionworks-sfm-repo Release [2,003 B]
Get:8 file:/var/visionworks-tracking-repo Release [2,008 B]
Hit:12 http://packages.ros.org/ros/ubuntu xenial InRelease
Get:14 http://archive.ubuntu.com/ubuntu xenial-security InRelease [107 kB]
Hit:15 http://packages.microsoft.com/repos/vscode stable InRelease
Hit:17 http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu xenial InRelease
Get:18 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [109 kB]
Hit:19 http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu xenial InRelease
Get:11 http://archive.ubuntu.com/ubuntu xenial InRelease [247 kB]
Get:20 http://archive.ubuntu.com/ubuntu xenial-security/main Sources [135 kB]
Get:21 http://archive.ubuntu.com/ubuntu xenial-security/restricted Sources [2,116 B]
Get:22 http://archive.ubuntu.com/ubuntu xenial-security/universe Sources [78.4 kB]
Get:23 http://archive.ubuntu.com/ubuntu xenial-security/multiverse Sources [2,088 B]
Get:24 http://archive.ubuntu.com/ubuntu xenial-security/main amd64 Packages [568 kB]
Get:25 http://archive.ubuntu.com/ubuntu xenial-security/main i386 Packages [490 kB]
Ign:26 http://archive.ubuntu.com/ubuntu xenial-security/main arm64 Packages
Hit:27 http://ppa.launchpad.net/webupd8team/java/ubuntu xenial InRelease
Get:28 http://archive.ubuntu.com/ubuntu xenial-security/main Translation-en [238 kB]
Get:29 http://archive.ubuntu.com/ubuntu xenial-security/main amd64 DEP-11 Metadata [67.7 kB]
Get:30 http://archive.ubuntu.com/ubuntu xenial-security/main DEP-11 64x64 Icons [68.0 kB]
Get:31 http://archive.ubuntu.com/ubuntu xenial-security/restricted amd64 Packages [7,204 B]
Get:32 http://archive.ubuntu.com/ubuntu xenial-security/restricted i386 Packages [7,224 B]
Get:33 http://archive.ubuntu.com/ubuntu xenial-security/restricted Translation-en [2,152 B]
Get:34 http://archive.ubuntu.com/ubuntu xenial-security/restricted amd64 DEP-11 Metadata [200 B]
Get:35 http://archive.ubuntu.com/ubuntu xenial-security/universe amd64 Packages [391 kB]
Get:36 http://archive.ubuntu.com/ubuntu xenial-security/universe i386 Packages [339 kB]
Ign:37 http://archive.ubuntu.com/ubuntu xenial-security/universe arm64 Packages
Get:38 http://archive.ubuntu.com/ubuntu xenial-security/universe Translation-en [149 kB]
Get:39 http://archive.ubuntu.com/ubuntu xenial-security/universe amd64 DEP-11 Metadata [108 kB]
Get:40 http://archive.ubuntu.com/ubuntu xenial-security/universe DEP-11 64x64 Icons [145 kB]
Get:41 http://archive.ubuntu.com/ubuntu xenial-security/multiverse amd64 Packages [3,460 B]
Get:42 http://archive.ubuntu.com/ubuntu xenial-security/multiverse i386 Packages [3,632 B]
Ign:43 http://archive.ubuntu.com/ubuntu xenial-security/multiverse arm64 Packages
Get:44 http://archive.ubuntu.com/ubuntu xenial-security/multiverse Translation-en [1,744 B]
Get:45 http://archive.ubuntu.com/ubuntu xenial-security/multiverse amd64 DEP-11 Metadata [212 B]
Get:46 http://archive.ubuntu.com/ubuntu xenial-security/multiverse DEP-11 64x64 Icons [29 B]
Get:47 http://archive.ubuntu.com/ubuntu xenial-updates/main Sources [322 kB]
Get:48 http://archive.ubuntu.com/ubuntu xenial-updates/restricted Sources [2,528 B]
Get:49 http://archive.ubuntu.com/ubuntu xenial-updates/universe Sources [224 kB]
Get:50 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse Sources [8,384 B]
Get:51 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages [860 kB]
Get:52 http://archive.ubuntu.com/ubuntu xenial-updates/main i386 Packages [771 kB]
Ign:53 http://archive.ubuntu.com/ubuntu xenial-updates/main arm64 Packages
Get:54 http://archive.ubuntu.com/ubuntu xenial-updates/main Translation-en [351 kB]
Get:55 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 DEP-11 Metadata [320 kB]
Get:56 http://archive.ubuntu.com/ubuntu xenial-updates/main DEP-11 64x64 Icons [227 kB]
Get:57 http://archive.ubuntu.com/ubuntu xenial-updates/restricted amd64 Packages [7,556 B]
Get:58 http://archive.ubuntu.com/ubuntu xenial-updates/restricted i386 Packages [7,524 B]
Get:59 http://archive.ubuntu.com/ubuntu xenial-updates/restricted Translation-en [2,272 B]
Get:60 http://archive.ubuntu.com/ubuntu xenial-updates/restricted amd64 DEP-11 Metadata [157 B]
Get:61 http://archive.ubuntu.com/ubuntu xenial-updates/universe amd64 Packages [694 kB]
Get:62 http://archive.ubuntu.com/ubuntu xenial-updates/universe i386 Packages [636 kB]
Ign:63 http://archive.ubuntu.com/ubuntu xenial-updates/universe arm64 Packages
Get:64 http://archive.ubuntu.com/ubuntu xenial-updates/universe Translation-en [280 kB]
Get:65 http://archive.ubuntu.com/ubuntu xenial-updates/universe amd64 DEP-11 Metadata [247 kB]
Get:66 http://archive.ubuntu.com/ubuntu xenial-updates/universe DEP-11 64x64 Icons [333 kB]
Get:67 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 Packages [16.4 kB]
Get:68 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse i386 Packages [15.5 kB]
Ign:69 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse arm64 Packages
Get:70 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse Translation-en [8,344 B]
Get:71 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 DEP-11 Metadata [5,960 B]
Get:72 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse DEP-11 64x64 Icons [14.3 kB]
Get:73 http://archive.ubuntu.com/ubuntu xenial/main Sources [868 kB]
Get:74 http://archive.ubuntu.com/ubuntu xenial/restricted Sources [4,808 B]
Get:75 http://archive.ubuntu.com/ubuntu xenial/universe Sources [7,728 kB]
Get:76 http://archive.ubuntu.com/ubuntu xenial/multiverse Sources [179 kB]
Get:77 http://archive.ubuntu.com/ubuntu xenial/main amd64 Packages [1,201 kB]
Get:78 http://archive.ubuntu.com/ubuntu xenial/main i386 Packages [1,196 kB]
Ign:79 http://archive.ubuntu.com/ubuntu xenial/main arm64 Packages
Get:80 http://archive.ubuntu.com/ubuntu xenial/main Translation-en_AU [420 kB]
Get:81 http://archive.ubuntu.com/ubuntu xenial/main Translation-en [568 kB]
Get:82 http://archive.ubuntu.com/ubuntu xenial/main amd64 DEP-11 Metadata [733 kB]
Get:83 http://archive.ubuntu.com/ubuntu xenial/main DEP-11 64x64 Icons [409 kB]
Get:84 http://archive.ubuntu.com/ubuntu xenial/restricted amd64 Packages [8,344 B]
Get:85 http://archive.ubuntu.com/ubuntu xenial/restricted i386 Packages [8,684 B]
Get:86 http://archive.ubuntu.com/ubuntu xenial/restricted Translation-en_AU [2,012 B]
Get:87 http://archive.ubuntu.com/ubuntu xenial/restricted Translation-en [2,908 B]
Get:88 http://archive.ubuntu.com/ubuntu xenial/restricted amd64 DEP-11 Metadata [186 B]
Get:89 http://archive.ubuntu.com/ubuntu xenial/universe amd64 Packages [7,532 kB]
Get:90 http://archive.ubuntu.com/ubuntu xenial/universe i386 Packages [7,512 kB]
Ign:91 http://archive.ubuntu.com/ubuntu xenial/universe arm64 Packages
Get:92 http://archive.ubuntu.com/ubuntu xenial/universe Translation-en_AU [3,039 kB]
Get:93 http://archive.ubuntu.com/ubuntu xenial/universe Translation-en [4,354 kB]
Get:94 http://archive.ubuntu.com/ubuntu xenial/universe amd64 DEP-11 Metadata [3,410 kB]
Get:95 http://archive.ubuntu.com/ubuntu xenial/universe DEP-11 64x64 Icons [7,448 kB]
Get:96 http://archive.ubuntu.com/ubuntu xenial/multiverse amd64 Packages [144 kB]
Get:97 http://archive.ubuntu.com/ubuntu xenial/multiverse i386 Packages [140 kB]
Ign:98 http://archive.ubuntu.com/ubuntu xenial/multiverse arm64 Packages
Get:99 http://archive.ubuntu.com/ubuntu xenial/multiverse Translation-en_AU [67.7 kB]
Get:100 http://archive.ubuntu.com/ubuntu xenial/multiverse Translation-en [106 kB]
Get:101 http://archive.ubuntu.com/ubuntu xenial/multiverse amd64 DEP-11 Metadata [63.8 kB]
Get:102 http://archive.ubuntu.com/ubuntu xenial/multiverse DEP-11 64x64 Icons [230 kB]
Ign:26 http://archive.ubuntu.com/ubuntu xenial-security/main arm64 Packages
Ign:37 http://archive.ubuntu.com/ubuntu xenial-security/universe arm64 Packages
Ign:43 http://archive.ubuntu.com/ubuntu xenial-security/multiverse arm64 Packages
Ign:53 http://archive.ubuntu.com/ubuntu xenial-updates/main arm64 Packages
Ign:63 http://archive.ubuntu.com/ubuntu xenial-updates/universe arm64 Packages
Ign:69 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse arm64 Packages
Ign:79 http://archive.ubuntu.com/ubuntu xenial/main arm64 Packages
Ign:91 http://archive.ubuntu.com/ubuntu xenial/universe arm64 Packages
Ign:98 http://archive.ubuntu.com/ubuntu xenial/multiverse arm64 Packages
Ign:26 http://archive.ubuntu.com/ubuntu xenial-security/main arm64 Packages
Ign:37 http://archive.ubuntu.com/ubuntu xenial-security/universe arm64 Packages
Ign:43 http://archive.ubuntu.com/ubuntu xenial-security/multiverse arm64 Packages
Ign:53 http://archive.ubuntu.com/ubuntu xenial-updates/main arm64 Packages
Ign:63 http://archive.ubuntu.com/ubuntu xenial-updates/universe arm64 Packages
Ign:69 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse arm64 Packages
Ign:79 http://archive.ubuntu.com/ubuntu xenial/main arm64 Packages
Ign:91 http://archive.ubuntu.com/ubuntu xenial/universe arm64 Packages
Ign:98 http://archive.ubuntu.com/ubuntu xenial/multiverse arm64 Packages
Err:26 http://archive.ubuntu.com/ubuntu xenial-security/main arm64 Packages
404 Not Found [IP: 91.189.91.23 80]
Ign:37 http://archive.ubuntu.com/ubuntu xenial-security/universe arm64 Packages
Ign:43 http://archive.ubuntu.com/ubuntu xenial-security/multiverse arm64 Packages
Err:53 http://archive.ubuntu.com/ubuntu xenial-updates/main arm64 Packages
404 Not Found [IP: 91.189.91.23 80]
Ign:63 http://archive.ubuntu.com/ubuntu xenial-updates/universe arm64 Packages
Ign:69 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse arm64 Packages
Err:79 http://archive.ubuntu.com/ubuntu xenial/main arm64 Packages
404 Not Found [IP: 91.189.91.23 80]
Ign:91 http://archive.ubuntu.com/ubuntu xenial/universe arm64 Packages
Ign:98 http://archive.ubuntu.com/ubuntu xenial/multiverse arm64 Packages
Fetched 1,998 kB in 4s (449 kB/s)
Reading package lists... Done
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-security/main/binary-arm64/Packages 404 Not Found [IP: 91.189.91.23 80]
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-updates/main/binary-arm64/Packages 404 Not Found [IP: 91.189.91.23 80]
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial/main/binary-arm64/Packages 404 Not Found [IP: 91.189.91.23 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.
答案1
ubuntu我遗漏了每行字符串后面的尾部斜杠sources.list。这些行应如下所示：
deb http://archive.ubuntu.com/ubuntu/ xenial main restricted universe multiverse
sudo apt update编辑后别忘了运行sources.list！