linux - yum update 到底做了什么工作

Question

yum update后,会得到类下面列表

freetype x86_64 2.3.11-17.el6 base 361 k
gawk x86_64 3.1.7-10.el6_7.3 base 780 k
gcc x86_64 4.4.7-17.el6 base 10 M
gcc-c++ x86_64 4.4.7-17.el6 base 4.7 M

最后

Total size: 292 M
Total download size: 291 M

yum update不是更新文件列表吗,为什么会下载这么多东西?

Answer 1

yum makecache ≈ apt-get update
yum update ≈ apt-get upgrade
Did you forget it?

Answer 2

You cannot directly enter yum update followed by the name of the service you want to upgrade. This is the entire upgrade including the system kernel, which can easily cause the system to crash.

Answer 3

man yum

Answer 4

yum update will update the system, and may update the kernel and cause the system to crash