我在终端中运行了这个命令：
sudo apt-get update
更新以以下错误报告结束：
W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://extras.ubuntu.com precise Release: The following signatures were invalid: BADSIG 16126D3A3E5C1192 Ubuntu Extras Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures were invalid: BADSIG 4C1CBC1B69B0E2F4 Launchpad PPA for Jonathan French
W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/precise/Release
这是什么意思，为什么会这样？
我错误地删除了resolvconf文件夹和resolv.conf文件/etc，假设 resolvconf 导致 UCK 失败。现在应用程序已经升级，解决了这个问题，但它说no file named resolv.conf in /etc。它说的是正确的，因为我删除了这些文件。有没有办法重新创建文件或从其他位置还原？
我在 11.04。安装 Kubuntu-desktop 后，我的 Ubuntu 闪屏被 Kubuntu 替换。我在这个askubuntu 链接中错误地遵循了 daniel kullmann 的回答，我丢失了闪屏。现在它在启动菜单后只显示一个空白屏幕，直到登录屏幕。我从同一个帖子中输入了其他命令，但什么也没改变。我怎样才能恢复初始屏幕？
我已经Nautilus用 root 权限打开删除了一些项目。当我输入时Sudo nautilus，特定的窗口打开了，但也出现了一些错误，如下所示：
meego@meego-Notebook-PC:~$ sudo nautilus
[sudo] password for meego:
Initializing nautilus-gdu extension
** (nautilus:5579): WARNING **: Failed to get the current CK session: GDBus.Error:org.freedesktop.ConsoleKit.Manager.GeneralError: Unable to lookup session information for process '5579'
(nautilus:5579): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed
Nautilus-Share-Message: Called "net usershare info" but it failed: 'net usershare' returned error 255: net usershare: cannot open usershare directory /var/lib/samba/usershares. Error No such file or directory
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