yum (Yellowdog Updater Modified)是一个集与查找，安装，更新和删除程序的Linux软件。它运行在RPM包兼容的Linux发行版本上，如：RedHat, Fedora, SUSE, CentOS, Mandriva。
今天我在用CentOS 5.5的yum命令安装的时候出现如下错误：
[root@malu2 ~]# yum install vim
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirror.hosting90.cz
* extras: mirror.hosting90.cz
* updates: mirror.hosting90.cz
Setting up Install Process
No package vim available.
Nothing to do
对于此错误，我一般习惯性先去更新一下yum仓库：
#yum -y update
再次运行安装，发现错误依旧，看来这种猜包名的方法不适用；所以接下来可以通过yum的查找参数来列出vim相关的包名:
[root@malu2 yum.repos.d]# yum search vim
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirror.hosting90.cz
* extras: mirror.hosting90.cz
* updates: mirror.hosting90.cz
===================== Matched: vim ===================
vim-X11.x86_64 : The VIM version of the vi editor for the X Window System.
vim-common.x86_64 : The common files needed by any version of the VIM editor.
vim-enhanced.x86_64 : A version of the VIM editor which includes recent
: enhancements.
vim-minimal.x86_64 : A minimal version of the VIM editor.
通过查看，我们可以看到，yum列出了详细的vim相关的包名，这样就可以顺利的安装vim了：
#yum -y install vim-enhanced.x86_64
以上命令就能执行成功了。当然不仅仅vim安装，其他程序比如mysql我们也同样只要先进行yum查找，再通过匹配详细包名来进行安装，就不会出现上述错误了
Yum的更新及安装操作
更新及安装：
yum install package 安装指定的安装包package
yum localinstall package 本地安装软件包
yum update 全部更新
yum update package 更新指定程序包package
yum check-update 检查可更新的程序
查找和显示
yum info <package> 显示安装包信息
yum list 显示所有已经安装和可以安装的程序包
yum list <package> 显示指定程序包安装情况
yum search <keyword>查找软件包
Yum和Apt-get对比
| Task | Red Hat/Fedora | Ubuntu/Debian |
| Adding, Removing and Upgrading Packages | ||
| Refresh list of available packages | Yum refreshes each time it’s used | apt-get update |
| Install a package from a repository | yum installpackage_name | apt-get installpackage_name |
| Install a package file | yum installpackage.rpmrpm -ipackage.rpm | dpkg –install package.deb |
| Remove a package | rpm -e package_name | apt-get removepackage_name |
| Check for package upgrades | yum check-update | apt-get -s upgradeapt-get -s dist-upgrade |
| Upgrade packages | yum updaterpm -Uvh [args] | apt-get dist-upgrade |
| Upgrade the entire system | yum upgrade | apt-get dist-upgrade |
| Package Information | ||
| Get information about an available package | yum searchpackage_name | apt-cache searchpackage_name |
| Show available packages | yum list available | apt-cache dumpavail |
| List all installed packages | yum list installedrpm -qa | dpkg –list |
| Get information about a package | yum info package_name | apt-cache showpackage_name |
| Get information about an installed package | rpm -qi package_name | dpkg –statuspackage_name |
| List files in an installed package | rpm -ql package_name | dpkg –listfilespackage_name |
| List documentation files in an installed package | rpm -qd package_name | - |
| List configuration files in an installed package | rpm -qc package_name | - |
| Show the packages a given package depends on | rpm -qR package_name | apt-cache depends |
| Show other packages that depend on agiven package (reverse dependency) | rpm -q -whatrequires [args] | apt-cache rdepends |
| Package File Information | ||
| Get information about a package file | rpm -qpi package.rpm | dpkg –info package.deb |
| List files in a package file | rpm -qpl package.rpm | dpkg –contentspackage.deb |
| List documentation files in a package file | rpm -qpd package.rpm | - |
| List configuration files in a package file | rpm -qpc package.rpm | - |
| Extract files in a package | rpm2cpio package.rpm | cpio -vid | dpkg-deb –extractpackage.deb dir-to-extract-to |
| Find package that installed a file | rpm -qf filename | dpkg –search filename |
| Find package that provides a particular file | yum provides filename | apt-file search filename |
| Misc. Packaging System Tools | ||
| Show stats about the package cache | - | apt-cache stats |
| Verify all installed packages | rpm -Va | debsums |
| Remove packages from the local cache directory | yum clean packages | apt-get clean |
| Remove only obsolete packages from the local cache directory | - | apt-get autoclean |
| Remove header files from the local cache directory(forcing a new download of same on next use) | yum clean headers | apt-file purge |
| General Packaging System Information | ||
| Package file extension | .rpm | .deb |
| Repository location configuration | /etc/yum.conf |
/etc/apt/sources.list |