YUM的简介

• 什么是yum源？
  Yum（全称为 Yellow dog Updater, Modified）是一个在Fedora、RedHat/RHEL、SUSE以及CentOS等Linux发行版中的/repo/【Shell】前端【软件包管理器】。

yum源 := yum仓库 := yum管理下的软件源/软件仓库

怎么生动地理解这一点呢？

yum 类同于 CENTOS操作系统的 软件管理器；Web前端开发的 npm 包(依赖)管理软件；Java后端开发的 maven 包(依赖)管理软件。

值得注意的是，CENTOS 8新增了 DNF 包管理器，以取代之前OS版本的 YUM。

2 YUM的常用命令

查看帮助信息

查看帮助信息[方式1] --> man yum

man yum

查看帮助信息[方式2] --> yum --help

yum --help

[root@node116 repo]# yum --help
Loaded plugins: fastestmirror, langpacks
Usage: yum [options] COMMAND

List of Commands:

check          Check for problems in the rpmdb
check-update   Check for available package updates
clean          Remove cached data
deplist        List a package's dependencies
distribution-synchronization Synchronize installed packages to the latest available versions
downgrade      downgrade a package
erase          Remove a package or packages from your system
fs             Acts on the filesystem data of the host, mainly for removing docs/lanuages for minimal hosts.
fssnapshot     Creates filesystem snapshots, or lists/deletes current snapshots.
groups         Display, or use, the groups information
help           Display a helpful usage message
history        Display, or use, the transaction history
info           Display details about a package or group of packages
install        Install a package or packages on your system
langavailable  Check available languages
langinfo       List languages information
langinstall    Install appropriate language packs for a language
langlist       List installed languages
langremove     Remove installed language packs for a language
list           List a package or groups of packages
load-transaction load a saved transaction from filename
makecache      Generate the metadata cache
provides       Find what package provides the given value
reinstall      reinstall a package
repo-pkgs      Treat a repo. as a group of packages, so we can install/remove all of them
repolist       Display the configured software repositories
search         Search package details for the given string
shell          Run an interactive yum shell
swap           Simple way to swap packages, instead of using shell
update         Update a package or packages on your system
update-minimal Works like upgrade, but goes to the 'newest' package match which fixes a problem that affects your system
updateinfo     Acts on repository update information
upgrade        Update packages taking obsoletes into account
version        Display a version for the machine and/or available repos.


Options:
  -h, --help            show this help message and exit
  -t, --tolerant        be tolerant of errors
  -C, --cacheonly       run entirely from system cache, don't update cache
  -c [config file], --config=[config file]
                        config file location
  -R [minutes], --randomwait=[minutes]
                        maximum command wait time
  -d [debug level], --debuglevel=[debug level]
                        debugging output level
  --showduplicates      show duplicates, in repos, in list/search commands
  -e [error level], --errorlevel=[error level]
                        error output level
  --rpmverbosity=[debug level name]
                        debugging output level for rpm
  -q, --quiet           quiet operation
  -v, --verbose         verbose operation
  -y, --assumeyes       answer yes for all questions
  --assumeno            answer no for all questions
  --version             show Yum version and exit
  --installroot=[path]  set install root
  --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
  --disableincludes=[repo]
                        disable includepkgs 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
  --releasever=RELEASEVER
                        set value of $releasever in yum config and repo files
  --downloadonly        don't update, just download
  --downloaddir=DLDIR   specifies an alternate directory to store packages
  --setopt=SETOPTS      set arbitrary config and repo options
  --bugfix              Include bugfix relevant packages, in updates
  --security            Include security relevant packages, in updates
  --advisory=ADVS, --advisories=ADVS
                        Include packages needed to fix the given advisory, in
                        updates
  --bzs=BZS             Include packages needed to fix the given BZ, in
                        updates
  --cves=CVES           Include packages needed to fix the given CVE, in
                        updates
  --sec-severity=SEVS, --secseverity=SEVS
                        Include security relevant packages matching the
                        severity, in updates

  Plugin Options:

查看 当前主机配置的yum源(软件仓库)列表

yum repolist

yum repolist enabled
  # 列出你当前系统【已启用】的yum repo

重建 yum 软件源的缓存

在更新yum源或者出现配置yum源之后，通常都会使用yum makecache 生成缓存。

把服务器的rpm软件包信息提前下载到本地主机缓存起来，用来提高搜索安装软件的速度
以后用install时就在缓存中搜索，提高了速度。

yum makecache
yum makecache fast
yum makecache all

更新 yum 源

yum update -y --skip-broken

清除 yum 软件源的缓存

yum 会把下载的软件包和header存储在cache中而不自动删除。如果觉得占用磁盘空间，可以使用yum clean指令清除缓存。

yum clean all

搜索软件包

yum search 软件包

yum -C search "关键词"