每当我输入命令
sudo apt-get update
它返回：
Ign http://security.ubuntu.com vivid-security InRelease
Ign http://us.archive.ubuntu.com vivid InRelease
Get:1 http://security.ubuntu.com vivid-security Release.gpg [933 B]
Ign http://us.archive.ubuntu.com vivid-updates InRelease
Ign http://archive.canonical.com vivid InRelease
Get:2 http://security.ubuntu.com vivid-security Release [63.5 kB]
Ign http://us.archive.ubuntu.com vivid-backports InRelease
Ign http://archive.canonical.com vivid InRelease
Hit http://us.archive.ubuntu.com vivid Release.gpg
Get:3 http://us.archive.ubuntu.com vivid-updates Release.gpg [933 B]
Hit http://archive.canonical.com vivid Release.gpg
Hit http://us.archive.ubuntu.com vivid-backports Release.gpg
Get:4 http://security.ubuntu.com vivid-security/main Sources [26.4 kB]
Hit http://archive.canonical.com vivid Release.gpg
Hit http://us.archive.ubuntu.com vivid Release
Get:5 http://security.ubuntu.com vivid-security/restricted Sources [28 B]
Get:6 http://us.archive.ubuntu.com vivid-updates Release [63.5 kB]
Hit http://archive.canonical.com vivid Release
Get:7 http://security.ubuntu.com vivid-security/universe Sources [12.3 kB]
Hit http://archive.canonical.com vivid Release
Hit http://us.archive.ubuntu.com vivid-backports Release
Get:8 http://us.archive.ubuntu.com vivid-updates/main Sources [59.1 kB]
Get:9 http://us.archive.ubuntu.com vivid-updates/restricted Sources [28 B]
Get:10 http://us.archive.ubuntu.com vivid-updates/universe Sources [26.7 kB]
Hit http://us.archive.ubuntu.com vivid-backports/main Sources
Hit http://us.archive.ubuntu.com vivid-backports/restricted Sources
Hit http://us.archive.ubuntu.com vivid/main Sources
Hit http://us.archive.ubuntu.com vivid/restricted Sources
Hit http://us.archive.ubuntu.com vivid/universe Sources
Hit http://us.archive.ubuntu.com vivid-backports/universe Sources
Fetched 253 kB in 4s (62.5 kB/s)
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/vivid-security/Release Unable to find expected entry 'main/binary-1386/Packages' in Release file (Wrong sources.list entry or malformed file)
W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/vivid/Release Unable to find expected entry 'main/binary-1386/Packages' in Release file (Wrong sources.list entry or malformed file)
W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/vivid-updates/Release Unable to find expected entry 'main/binary-1386/Packages' in Release file (Wrong sources.list entry or malformed file)
W: Failed to fetch http://archive.canonical.com/ubuntu/dists/vivid/Release Unable to find expected entry 'partner/binary-1386/Packages' in Release file (Wrong sources.list entry or malformed file)
W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/vivid-backports/Release Unable to find expected entry 'main/binary-1386/Packages' in Release file (Wrong sources.list entry or malformed file)
W: Failed to fetch http://archive.canonical.com/dists/vivid/Release Unable to find expected entry 'partner/binary-1386/Packages' in Release file (Wrong sources.list entry or malformed file)
E: Some index files failed to download. They have been ignored, or old ones used instead.
请帮忙。我尝试安装 skype 已经很长时间了，也尝试了无数种解决方法。
更新：由于这个原因，我也无法安装 steam。
答案1
我有时也遇到同样的问题。我猜你什么都安装不了，对吧？我用 2 个解决方案解决了这个问题。
首先尝试更好的镜像进行更新。
从图形模式中查找最快的镜像非常容易。您只需打开 Synaptic 包管理器，转到设置 -> 存储库。从 Ubuntu 软件部分，在“下载自”下拉框中选择“其他”，然后单击选择最佳镜像。
其次，删除所有不起作用的 ppa。
使用 GUI 删除 PPA：也可以通过打开软件源（Ubuntu 软件中心 > 编辑 > 软件源），然后转到“其他软件”选项卡，选择要删除的 PPA，然后单击“删除”按钮来删除 PPA。
每个 PPA 此处应有两行，一行用于编译的包，一行用于源代码，因此请删除这两行。
其中之一也许能帮助你。