debian 源能调整优先级吗

借问一下，什么叫源优先级？
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--来自骗经验的XX贴吧客户端(^_^)

/etc/apt/sources.list
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# testing #
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deb http://ftp.us.debian.org/debiantesting main contrib non-free
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# unstable #
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deb http://ftp.us.debian.org/debian unstable main contrib non-free
In this example, we're pulling from testing and unstable. You could, of course, modify this to pull from stable as well.
/etc/apt/preferences
The 'preferences' file is where the actual pinning takes place. Here's an example:
Package: *Pin:
release a=testing
Pin-Priority: 900
Package: *Pin:
release a=unstable
Pin-Priority: 800
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https://wiki.debian.org/AptPreferences
很多时候百度不行谷歌试试

aptpreferences