今天在安裝vim的時候出現了Package has no installation candidate的問題，如：
# apt-get install
Reading package lists... Done
Building dependency tree... Done
Package aptitude is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'vim' has no installation
candidate
解決方法如下：
# apt-get update
【更新同步安裝列表。在這一步之前可能還需要添加新的源，比如
vi /etc/apt/sources.list 我添加了2個
deb http://mirrors.163.com/ubuntu/ hardy main universe
deb http://tw.archive.ubuntu.com/ubuntu/ hardy main universe
】
# apt-get upgrade【升級所有可升級的已安裝包？我沒做這一步，也可以】
# apt-get install
這樣就可以正常使用apt-get了。