ubuntu 错误：E: Some index files failed to download. They have been ignored, or old ones used instead.

执行命令：sudo apt-get update

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.

/var/lib/apt/lists/partial/下的所有文件删除 ，但会出现

E:Encountered a section with no Package: header, E:Problem with MergeList /var/lib/apt/lists/cn.archive.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages

sudo rm /var/lib/apt/lists/* -vf

sudo apt-get update