Yum配置文件位于/etc/yum.conf和/etc/yum.repos.d/CentOS-Base.repo目錄下
使用yum時(shí)注意：必須使用root身份來(lái)執(zhí)行yum；yum配置文件內(nèi)的鏡像站點(diǎn)必須能與自己進(jìn)行網(wǎng)絡(luò)連接；鏡像站點(diǎn)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(gè)軟件，后跟軟件名稱
search：Search package details for the given string 搜索某個(gè)軟件或重要關(guān)鍵字
list：List a package or groups of packages列出yum所管理的軟件名稱與版本，類似于rpm –qa
info：Display details about a package or group of packages，類似于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(jí)整個(gè)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(guān)系，在使用本地源軟件包進(jìn)行安裝時(shí)，可以查看依賴關(guān)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(shù)據(jù)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
-y：answer yes for all questions當(dāng)yum詢問(wèn)用戶意見時(shí)，主動(dòng)回答yes不需由鍵盤輸入
-installroot=[path]：set install root安裝在其他的路徑，而不再當(dāng)前目錄樹的架構(gòu)中
-h --help：show this help message and exit
-t --tolerant：be tolerant of errors
-C：run entirely from cache, don't update cache
-c：[config file]config file location
-R [minutes] maximum command wait time
-d [debug level] debugging output level
-showduplicates show duplicates, in repos, in list/search commands
-e [error level] error output level
-q, --quiet quiet operation
-v, --verbose verbose operation
-version show Yum version and exit
-enablerepo=[repo] enable one or more repositories (wildcards allowed)
-disablerepo=[repo] disable one or more repositories (wildcards allowed)
-x[package], --exclude=[package]exclude package(s) by name or glob
-disableexcludes=[repo]disable exclude from main, for a repo or for everything
-obsoletes：enable obsoletes processing during updates
-noplugins：disable Yum plugins
-nogpgcheck：disable gpg signature checking
-disableplugin=[plugin] disable plugins by name
-enableplugin=[plugin] enable plugins by name
-skip-broken：skip packages with depsolving problems
-color=COLOR： control whether color is used
[root@localhost ~]# yum search gcc 查找主機(jī)上是否有g(shù)cc的相關(guān)軟件，如果有，就會(huì)陳列出來(lái)。
[root@localhost ~]# yum info gcc 列出已安裝的yum所管理的軟件名稱與版本
……………………………………………………………………
Name：gcc
Arch：i386
Version： 4.1.2
Release： 48.el5
Size：9.6 M
Repo：installed
Summary：各類編譯器（C、C++、Objective-C、Java, ...）
URL：http://gcc.gnu.org
License：GPL
Description：The gcc package contains the GNU Compiler Collection version 4.1.You'll need this package in order to compile c code
……………………………………………………………………
顯示該軟件版本名稱，數(shù)據(jù)大小，軟件出處等信息。需要注意summary和description的信息
可以依據(jù)yum search 軟件名查找此軟件的信息，yum list軟件名 列出此軟件的版本和名稱，決定是否安裝此軟件。
安裝之前使用rpm –q 軟件名，查看此軟件是否安裝，如沒(méi)有安裝，使用yum install 軟件名 進(jìn)行安裝
使用yum可以主動(dòng)處理好依賴關(guān)系，下載好的軟件一般都放置在/var/cache/yum中，可以清除以節(jié)省磁盤空間。
[root@localhost ~]# yum clean packages #清除下載的軟件包
[root@localhost ~]# yum -y update #手動(dòng)系統(tǒng)更新
