22.文件系统――使用yum查看软件包
一、yum命令的基本查询功能
yum有很多子命令，它的基本格式是：
yum SubCommand File_Name | Package_Name
可以使用man来查看一下yum的帮助信息：
[root@localhost ~]# man yum
command is one of:
* repolist [all|enabled|disabled]：显示当前使用的仓
* list [...] ： 显示相关程序包，list子命令还有很多选项可用：
yum list [all | glob_exp1] [glob_exp2] [...]：显示所有的软件包
yum list available [glob_exp1] [...]：可用的软件包
yum list updates [glob_exp1] [...]：可升级的软件包
yum list installed [glob_exp1] [...]：已经安装的软件包
yum list extras [glob_exp1] [...]：当前系统上已安装的，但环境中配置的repository里没有的软件包
yum list obsoletes [glob_exp1] [...]：当前系统上已安装的，但环境配置的repository例已经废弃的软件包
yum list recent: 新添加进来的rpm包
* info [...]：yum info package_name: 显示软件包的摘要信息，有点类似于rpm -qi命令
* clean [ packages | metadata | expire-cache | rpmdb | plugins | all ]:
本地的缓存可能不能及时更新，需要清空，使用该命令来管理本地缓存
* makecache 清理了缓存后可以手段建立缓存
* groupinfo “group_name” ：跟组名相关的信息
* groupinstall group1 [group2] [...]: 可以使用yum 来安装一组软件包，即包组
* grouplist [hidden] [groupwildcard] [...]: 查看包组的信息
二、yum命令实例演示
/*--------yum list命令演示--------*/
首先使用yum命令结合其list子命令来查看一下仓库里的包的信息
如果只想显示特定的包，list子命令可以通配符使用：
[root@localhost yum.repos.d]# yum list all bind*
# 只想显示bind开头的包 Failed to set locale, defaulting to C Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile Installed Packages # 以下是已经安装的包 bind-chroot.x86_64 32:9.8.2-0.17.rc1.el6_4.6 installed bind-libs.x86_6432:9.8.2-0.17.rc1.el6_4.6 @anaconda-CentOS-201311272149.x86_64/6.5 bind-utils.x86_6432:9.8.2-0.17.rc1.el6_4.6 @anaconda-CentOS-201311272149.x86_64/6.5 Available Packages # 以下是可以安装的包 bind.x86_64 32:9.8.2-0.17.rc1.el6_4.6 base bind-devel.i686 32:9.8.2-0.17.rc1.el6_4.6 base bind-devel.x86_64 32:9.8.2-0.17.rc1.el6_4.6 base bind-dyndb-ldap.x86_64 2.3-5.el6 base bind-libs.i686 32:9.8.2-0.17.rc1.el6_4.6 base bind-sdb.x86_64 32:9.8.2-0.17.rc1.el6_4.6 base
[root@localhost yum.repos.d]# yum list installed bind*
# 使用installed选项查看已安装的bind开头的包 Failed to set locale, defaulting to C Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile Installed Packages bind-chroot.x86_64 32:9.8.2-0.17.rc1.el6_4.6 installed bind-libs.x86_64 32:9.8.2-0.17.rc1.el6_4.6 @anaconda-CentOS-201311272149.x86_64/6.5 bind-utils.x86_64 32:9.8.2-0.17.rc1.el6_4.6 @anaconda-CentOS-201311272149.x86_64/6.5
[root@localhost yum.repos.d]# yum list available bind*
# 使用available选项查看可安装的bind开头的包 Failed to set locale, defaulting to C Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile Available Packages bind.x86_64 32:9.8.2-0.17.rc1.el6_4.6 base bind-devel.i686 32:9.8.2-0.17.rc1.el6_4.6 base bind-devel.x86_64 32:9.8.2-0.17.rc1.el6_4.6 base bind-dyndb-ldap.x86_64 2.3-5.el6 base bind-libs.i686 32:9.8.2-0.17.rc1.el6_4.6 base bind-sdb.x86_64 32:9.8.2-0.17.rc1.el6_4.6 base
/*--------yum list命令演示--------*/
[root@localhost yum.repos.d]# yum repolist
# 使用yum repolist可以查看当前使用的yum仓库 Failed to set locale, defaulting to C Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile repo id repo name status base CentOS 6.4 x86_64 6367 #只有一个仓库，叫做base我们自己定义的描述一共有6367个包 repolist: 6367
[root@localhost ~]# yum repolist all
# 加上all选项可以看到所有的yum仓库，包括已被禁用的yum仓库 Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile repo id repo name status C6.0-base CentOS-6.0 - Base disabled C6.0-centosplus CentOS-6.0 - CentOSPlus disabled ... C6.3-updates CentOS-6.3 - Updates disabled base CentOS 6.4 x86_64 enabled: 6,367 repolist: 6,367
命令repolist默认显示的是enable的仓库。
/*--------yum info命令演示--------*/
使用yum info命令可以获取软件包的摘要信息
[root@localhost ~]# yum info zsh
Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile Installed Packages # 显示了这个软件包是已经安装的还是没有安装的 Name : zsh Arch : x86_64 Version : 4.3.10 Release : 7.el6 Size : 4.8 M Repo : installed Summary : A powerful interactive shell URL : http://zsh.sunsite.dk/ License : BSD Description : The zsh shell is a command interpreter usable as an interactive login : shell and as a shell script command processor. Zsh resembles the ksh : shell (the Korn shell), but includes many enhancements. Zsh supports : command line editing, built-in spelling correction, programmable : command completion, shell functions (with autoloading), a history : mechanism, and more.
该命令虽然没有rpm -qi命令显示的信息全面，但也提供了很多有用的信息，如该软件包是否已经安装了：
[root@localhost ~]# yum info bind
Loaded plugins: fastestmirror, refresh-packagekit, security Loading mirror speeds from cached hostfile Available Packages # 没有安装的软件包可能会显示为Available Packages Name : bind Arch : x86_64 Epoch : 32 Version : 9.8.2 Release : 0.17.rc1.el6_4.6 Size : 4.0 M Repo : base Summary : The Berkeley Internet Name Domain (BIND) DNS (Domain Name System) server URL : http://www.isc.org/products/BIND/ License : ISC Description : BIND (Berkeley Internet Name Domain) is an implementation of the DNS : (Domain Name System) protocols. BIND includes a DNS server (named), : which resolves host names to IP addresses; a resolver library : (routines for applications to use when interfacing with DNS); and : tools for verifying that the DNS server is operating properly.
之所以能显示没有安装的软件包的相关信息，是因为yum仓库中提供了这些包的信息，可以自动获取。
/*--------yum grouplist命令演示获取包组信息--------*/
[root@localhost ~]# yum grouplist
Loaded plugins: fastestmirror, refresh-packagekit, security Setting up Group Process Loading mirror speeds from cached hostfile Installed Groups: Additional Development Base Debugging Tools Desktop Desktop Debugging and Performance Tools ... Xhosa Support [xh] Zulu Support [zu] Done
/*--------yum groupinfo命令演示获取包组的具体包信息--------*/
[root@localhost ~]# yum groupinfo "Development tools"
# 注意包名要使用双引号 Loaded plugins: fastestmirror, refresh-packagekit, security Setting up Group Process Loading mirror speeds from cached hostfile Group: Development tools Description: A basic development environment. Mandatory Packages: # 强制安装的包 autoconf rpm-build Default Packages: # 默认安装的包 byacc cscope Systemtap Optional Packages: # 可选安装的包 ElectricFence ant systemtap-sdt-devel systemtap-server
/*--------yum clean命令演示清空缓存--------*/
[root@localhost ~]# yum list
# 当前的仓库内容 yum-plugin-tsflags.noarch 1.1.30-14.el6 base ... zlib-devel.x86_64 1.2.3-29.el6 base zlib-static.x86_64 1.2.3-29.el6 base zsh-html.x86_64
[root@localhost ~]# yum clean all
# 清空缓存 Loaded plugins: fastestmirror, refresh-packagekit, security Cleaning repos: base Cleaning up Everything Cleaning up list of fastest mirrors
完全清空缓存代价较大，建议只清理元数据metadata：
[root@localhost ~]# yum clean metadata
Loaded plugins: fastestmirror, refresh-packagekit, security Cleaning repos: base 4 metadata files removed 3 sqlite files removed 0 metadata files removed
[root@localhost ~]# yum list
# 更新到最新的list Loaded plugins: fastestmirror, refresh-packagekit, security Determining fastest mirrors base | 4.0 kB 00:00 ... base/primary_db ... zlib-devel.x86_64 1.2.3-29.el6 base zlib-static.x86_64 1.2.3-29.el6 base zsh-html.x86_64 4.3.10-7.el6 base
/*--------yum makecache命令演示手动建立缓存--------*/
[root@localhost ~]# yum clean all
Loaded plugins: fastestmirror, refresh-packagekit, security Cleaning repos: base Cleaning up Everything Cleaning up list of fastest mirrors
[root@localhost ~]# yum makecache
Loaded plugins: fastestmirror, refresh-packagekit, security Determining fastest mirrors base | 4.0 kB 00:00 ... base/group_gz | 220 kB 00:00 ... base/filelists_db | 5.8 MB 00:00 ... base/primary_db | 4.4 MB 00:00 ... base/other_db | 2.7 MB 00:00 ... Metadata Cache Created