apt-get upgarde和dist-upgrade的差别

时间:2022-05-17 14:11:02

apt-get upgarde和dist-upgrade的差别

apt-get upgarde和dist-upgrade的差别

Debian/Ubuntu Linux都使用apt,升级时都是: 
  www.2cto.com  
apt-get update 
apt-get upgrade 
apt-get dist-upgrade 
但是常常有人会问, 
upgrade和dist-upgrade有何不同,仔细查查,似乎大家对upgrade和dist-upgrade的解释
都有点不同,在此也纪录自己的看法. 
我认为apt-get 
upgrade和dist-upgrade的差别:   www.2cto.com  
upgrade:系统将现有的Package升级,如果有相依性的问题,而此相依性需要安装其它新的
Package或影响到其它Package的相依性时,此Package就不会被升级,会保留下来. 
dist-upgrade:可以聪明的解决相依性的问题,如果有相依性问题,需要安装/移除新的Package,
就会试着去安装/移除它. 
(所以通常这个会被认为是有点风险的升级) 
apt-get upgrade 和 apt-get dist-upgrade 本质上是没有什么不同的。
只不过,dist-upgrade 
会识别出当依赖关系改变的情形并作出处理,而upgrade对此情形不处理。
例如软件包 a 原先依赖 b c d,但是在源里面可能已经升级了,现在是 a 依赖 b c 
e。这种情况下,dist-upgrade 会删除 d 安装 e,并把 a 软件包升级,而 upgrade 会认为
依赖关系改变而拒绝升级 a 
软件包。  www.2cto.com  
man apt-get的解释: 
upgrade: upgrade is 
used to install the newest versions of all packages currently installed on the 
system from the sources enumerated in /etc/apt/sources.list. Packages currently 
installed with new versions available are retrieved and upgraded; under no 
circumstances are currently installed packages removed, or packages not already 
installed retrieved and installed. New versions of currently installed packages 
that cannot be upgraded without changing the install status of another package 
will be left at their current version. An update must be performed first so that 
apt-get knows that new versions of packages are available. 
dist-upgrade: dist-upgrade in addition to performing 
the function of upgrade, also intelligently handles changing dependencies with 
new versions of packages; apt-get has a "smart" conflict resolution system, and 
it will attempt to upgrade the most important packages at the expense of 
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