问题一：
执行命令
sudo apt-get update
错误描述如下：
W: Failed to fetch http://mirrors.sohu.com/ubuntu/dists/precise/universe/i18n/Index No Hash entry in Release file /var/lib/apt/lists/partial/mirrors.sohu.com_ubuntu_dists_precise_universe_i18n_Index W: Failed to fetch bzip2:/var/lib/apt/lists/partial/mirrors.sohu.com_ubuntu_dists_precise-updates_main_binary-i386_Packages Hash Sum mismatch W: Failed to fetch bzip2:/var/lib/apt/lists/partial/extras.ubuntu.com_ubuntu_dists_precise_main_binary-i386_Packages Hash Sum mismatch E: Some index files failed to download. They have been ignored, or old ones used instead.
解决方法：
将/var/lib/apt/lists/partial/下的所有文件删除，但是这可以解决大部分问题，个别源不能解决，如"/var/lib/apt/lists/partial/extras.ubuntu.com_ubuntu_dists_precise_main_binary-i386_Packages"，无耐进入/var/lib/apt/lists/将对应的文件删除
问题二：
无法找到对应的KEY
W:GPG error: not available: NO_PUBKEY 40976EAF437D05B5W:GPG error: not available: NO_PUBKEY 40976EAF437D05B5W:GPG error: not available: NO_PUBKEY 40976EAF437D05B5W:GPG error: not available: NO_PUBKEY 40976EAF437D05B5W:GPG error: not available: NO_PUBKEY 40976EAF437D05B5 |
解决方法：
使用如下命令：
gpg --keyserver subkeys.pgp.net --recv-keys40976EAF437D05B5 |
gpg -a --export 40976EAF437D05B5 | sudo apt-key add -