我是 ubuntu 新手。目前我想使用 watchdog 包在 Ubuntu 16.04.1 中运行 python 脚本。因此我使用以下注释安装 watchdog 包：
sudo apt-get install watchdog
然后，我收到了这条消息：
Reading package lists... Done
Building dependency tree
Reading state information... Done
watchdog is already the newest version (5.14-3ubuntu0.16.04.1).
0 upgraded, 0 newly installed, 0 to remove and 485 not upgraded.
然后我重启 ubuntu。当我使用以下注释检查软件包是否安装成功时：
apt list --installed
但是，我没有发现安装了看门狗包。
在安装看门狗之前，我还使用以下注释升级了软件包：
sudo apt-get update
然而，我收到了以下消息：
Fetched 6,704 kB in 58s (114 kB/s)
Reading package lists... Done
E: Failed to fetch http://security.ubuntu.com/ubuntu/di...cons-64x64.tar Could not open file /var/lib/apt/lists/partial/security.ubuntu.com_ubuntu_dists_xenial-security_main_dep11_icons-64x64.tar.gz - open (13: Permission denied)
E: Failed to fetch http://sg.archive.ubuntu.com/ubuntu/...cons-64x64.tar Could not open file /var/lib/apt/lists/partial/sg.archive.ubuntu.com_ubuntu_dists_xenial-updates_main_dep11_icons-64x64.tar.gz - open (13: Permission denied)
E: Failed to fetch http://sg.archive.ubuntu.com/ubuntu/...cons-64x64.tar Could not open file /var/lib/apt/lists/partial/sg.archive.ubuntu.com_ubuntu_dists_xenial-backports_main_dep11_icons-64x64.tar.gz - open (13: Permission denied)
E: Some index files failed to download. They have been ignored, or old ones used instead.
请问如何在 ubuntu 中安装 watchdog 包？
谢谢