备份与清理

* 备份快速设置已下载的部分软件包，以便重装系统再次使用，免去重新下载的时间

tar cizvf backup.tar.gz /var/cache/apt/archives --exclude=/var/cache/apt/archives/partial/* --exclude=/var/cache/apt/archives/lock

重装系统，设置好源列表后，导入已备份的软件包即可，操作方法：sudo apt-get update && sudo tar xzvf backup.tar.gz -C /

* 清理

sudo apt-get clean
rm -rf ~/.thumbnails/fail/gnome-thumbnail-factory/*
用上面的方法备份后，没有备份源文件，现在忘记了之前使用的源，怎么还原阿？

root@hj-laptop:~# sudo apt-get update && sudo tar xzvf backup.tar.gz -C /
Err http://cn.archive.ubuntu.com hardy Release.gpg
Could not resolve 'cn.archive.ubuntu.com'
Err http://cn.archive.ubuntu.com hardy-updates Release.gpg
Could not resolve 'cn.archive.ubuntu.com'
Err http://security.ubuntu.com hardy-security Release.gpg
Could not resolve 'security.ubuntu.com'
Reading package lists... Done
W: Failed to fetch http://cn.archive.ubuntu.com/ubuntu/dis ... elease.gpg Could not resolve 'cn.archive.ubuntu.com'

W: Failed to fetch http://cn.archive.ubuntu.com/ubuntu/dis ... elease.gpg Could not resolve 'cn.archive.ubuntu.com'

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists ... elease.gpg Could not resolve 'security.ubuntu.com'

W: Some index files failed to download, they have been ignored, or old ones used instead.
W: You may want to run apt-get update to correct these problems
tar: backup.tar.gz: Cannot open: No such file or directory
tar: Error is not recoverable: exiting now
tar: Child returned status 2
tar: Error exit delayed from previous errors
root@hj-laptop:~# sudo apt-get update && sudo tar xzvf backup.tar.gz -C /
Hit http://mirror.rootguide.org hardy Release.gpg
Hit http://mirror.rootguide.org hardy-updates Release.gpg
Hit http://mirror.rootguide.org hardy-security Release.gpg
Hit http://mirror.rootguide.org hardy Release
Hit http://mirror.rootguide.org hardy-updates Release
Hit http://mirror.rootguide.org hardy-security Release
Hit http://mirror.rootguide.org hardy/main Packages
Hit http://mirror.rootguide.org hardy/restricted Packages
Hit http://mirror.rootguide.org hardy/main Sources
Hit http://mirror.rootguide.org hardy/restricted Sources
Hit http://mirror.rootguide.org hardy/universe Packages
Hit http://mirror.rootguide.org hardy/universe Sources
Hit http://mirror.rootguide.org hardy/multiverse Packages
Hit http://mirror.rootguide.org hardy/multiverse Sources
Hit http://mirror.rootguide.org hardy-updates/main Packages
Hit http://mirror.rootguide.org hardy-updates/restricted Packages
Hit http://mirror.rootguide.org hardy-updates/main Sources
Hit http://mirror.rootguide.org hardy-updates/restricted Sources
Hit http://mirror.rootguide.org hardy-updates/universe Packages
Hit http://mirror.rootguide.org hardy-updates/universe Sources
Hit http://mirror.rootguide.org hardy-updates/multiverse Packages
Hit http://mirror.rootguide.org hardy-updates/multiverse Sources
Hit http://mirror.rootguide.org hardy-security/main Packages
Hit http://mirror.rootguide.org hardy-security/restricted Packages
Hit http://mirror.rootguide.org hardy-security/main Sources
Hit http://mirror.rootguide.org hardy-security/restricted Sources
Hit http://mirror.rootguide.org hardy-security/universe Packages
Hit http://mirror.rootguide.org hardy-security/universe Sources
Hit http://mirror.rootguide.org hardy-security/multiverse Packages
Hit http://mirror.rootguide.org hardy-security/multiverse Sources
Reading package lists... Done
tar: backup.tar.gz: Cannot open: No such file or directory
tar: Error is not recoverable: exiting now
tar: Child returned status 2
tar: Error exit delayed from previous errors
root@hj-laptop:~#


刚才弄了下，出现上面的了，什么意思？