Yum配置文件位於/etc/yum.conf和/etc/yum.repos.d/CentOS-Base.repo目錄下
使用yum時注意：必須使用root身份來執行yum；yum配置文件內的鏡像站點必須能與自己進行網絡連接；鏡像站點越近，帶寬越大越好，方便下載。
[root@localhost ~]# yum [options] COMMAND 軟件
List of Commands：
install：Install a package or packages on your system
update：Update a package or packages on your system
remove：移出某個軟件，後跟軟件名稱
search：Search package details for the given string 搜索某個軟件或重要關鍵字
list：List a package or groups of packages列出yum所管理的軟件名稱與版本，www.linuxidc.com類似於rpm –qa
info：Display details about a package or group of packages，類似於rpm –qai
clean：Remove cached data 下載文件被放置在/var/cache/yum中，可以使用clean清除。
check-update：Check for available package updates
Groupinfo：Display details about a package group
groupinstall Install the packages in a group on your system
grouplist：List available package groups
groupremove：Remove the packages in a group from your system
groupupdate：升級整個軟件群組
help：Display a helpful usage message
Deplist：List a package's dependencies 列出軟件包的依賴關系，在使用本地源軟件包進行安裝時，可以查看依賴關系
Downgrade：downgrade a package
Erase：Remove a package or packages from your system
localinstall：Install a local RPM安裝本地的rpm軟件包
makecache：Generate the metadata cache 生成數據緩存
provides：Find what package provides the given value 找到包提供的給定值
reinstall：reinstall a package 重裝軟件包
repolist：Display the configured software repositories
resolvedep：Determine which package provides the given dependency
shell：Run an interactive yum shell
upgrade：Update packages taking obsoletes into account
