我正在运行 Ubuntu GNOME 16.04.1。我正在尝试按照此处的说明安装 Elegance Colors 主题：https://github.com/numixproject/elegance-colors
但是，我无法安装它，因为“找不到包”。我按照链接中所示在终端中写入了完全相同的语句，但仍然不起作用。这是我在终端中得到的输出：
anurag@Anurag-Lenovo-G50-80:~$ sudo add-apt-repository ppa:satyajit-happy/themes
[sudo] password for anurag:
This PPA contains various themes for Gnome and Xfce.
More info: https://launchpad.net/~satyajit-happy/+archive/ubuntu/themes
Press [ENTER] to continue or ctrl-c to cancel adding it
gpg: keyring `/tmp/tmpbb1ar3tg/secring.gpg' created
gpg: keyring `/tmp/tmpbb1ar3tg/pubring.gpg' created
gpg: requesting key 5F0D930C from hkp server keyserver.ubuntu.com
gpg: /tmp/tmpbb1ar3tg/trustdb.gpg: trustdb created
gpg: key 5F0D930C: public key "Launchpad PPA for Satyajit Sahoo" imported
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
OK
anurag@Anurag-Lenovo-G50-80:~$ sudo apt-get update
Hit:1 http://us.archive.ubuntu.com/ubuntu xenial InRelease
Get:2 http://security.ubuntu.com/ubuntu xenial-security InRelease [94.5 kB]
Get:3 http://us.archive.ubuntu.com/ubuntu xenial-updates InRelease [95.7 kB]
Hit:4 http://archive.canonical.com/ubuntu xenial InRelease
Ign:5 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial InRelease
Hit:6 http://us.archive.ubuntu.com/ubuntu xenial-backports InRelease
Ign:7 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial Release
Get:8 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages [328 kB]
Ign:9 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 Packages
Ign:10 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main i386 Packages
Get:11 http://us.archive.ubuntu.com/ubuntu xenial-updates/main i386 Packages [323 kB]
Get:12 http://us.archive.ubuntu.com/ubuntu xenial-updates/universe amd64 Packages [300 kB]
Ign:13 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main all Packages
Get:14 http://us.archive.ubuntu.com/ubuntu xenial-updates/universe i386 Packages [297 kB]
Ign:15 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en_US
Ign:16 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en
Ign:17 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:18 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main DEP-11 64x64 Icons
Ign:9 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 Packages
Ign:10 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main i386 Packages
Ign:13 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main all Packages
Ign:15 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en_US
Ign:16 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en
Ign:17 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:18 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main DEP-11 64x64 Icons
Ign:9 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 Packages
Ign:10 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main i386 Packages
Ign:13 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main all Packages
Ign:15 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en_US
Ign:16 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en
Ign:17 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:18 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main DEP-11 64x64 Icons
Ign:9 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 Packages
Ign:10 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main i386 Packages
Ign:13 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main all Packages
Ign:15 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en_US
Ign:16 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en
Ign:17 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:18 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main DEP-11 64x64 Icons
Ign:9 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 Packages
Ign:10 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main i386 Packages
Ign:13 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main all Packages
Ign:15 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en_US
Ign:16 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en
Ign:17 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:18 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main DEP-11 64x64 Icons
Err:9 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 Packages
404 Not Found
Ign:10 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main i386 Packages
Ign:13 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main all Packages
Ign:15 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en_US
Ign:16 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main Translation-en
Ign:17 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:18 http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial/main DEP-11 64x64 Icons
Fetched 1,439 kB in 5s (287 kB/s)
Reading package lists... Done
W: The repository 'http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://ppa.launchpad.net/satyajit-happy/themes/ubuntu/dists/xenial/main/binary-amd64/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
anurag@Anurag-Lenovo-G50-80:~$ sudo apt-get install gnome-shell-theme-elegance-colors
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package gnome-shell-theme-elegance-colors
我不知道原因是什么，也不知道该如何解决。我非常喜欢这个主题，想要它。请帮忙。
谢谢。
答案1
问题是你添加的 PPA 不支持你的 Ubuntu 版本 (16.04，Xenial)。也就是说，没有可用的软件包。正如你从这里PPA 仅包含适用于 15.10 及更早版本的软件包。
为了能够安装该包，请转到/etc/apt/sources.list.d/，然后打开名为 的文件/etc/apt/sources.list.d/satyajit-happy-themes-xenial.list。在里面，您将看到以下内容：
deb http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial main
# deb-src http://ppa.launchpad.net/satyajit-happy/themes/ubuntu xenial main
xenial将单词改为wily。保存并sudo apt-get update再次运行。
现在你的机器将连接到该包的 Wily 存储库，找到这里，并将为您提供所需应用程序的最新可用软件包。