在使用git时，出现“git: command not found”的情况，于是使用yum安装：
[root@localhost ~]# yum install -y git
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: centos.ustc.edu.cn
* extras: centos.ustc.edu.cn
* updates: centos.ustc.edu.cn
Setting up Install Process
No package git available.
Nothing to do
需要先添加EPEL(Extra Packages for Enterprise Linux) repository：
[root@localhost ~]# rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm
Retrieving http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm
warning: /var/tmp/rpm-xfer.GsvZWW: Header V3 DSA signature: NOKEY, key ID 217521f6
Preparing... ########################################### [100%]
1:epel-release ########################################### [100%]
现在可以使用yum安装了
[root@localhost ~]# yum install -y git
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: centos.ustc.edu.cn
* epel: mirrors.ustc.edu.cn
* extras: centos.ustc.edu.cn
* updates: centos.ustc.edu.cn
epel | 3.4 kB 00:00
epel/primary_db | 3.1 MB 00:01
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package git.i386 0:1.7.4.1-1.el5 set to be updated
--> Processing Dependency: perl-Git = 1.7.4.1-1.el5 for package: git
--> Processing Dependency: perl(Error) for package: git
--> Processing Dependency: perl(Git) for package: git
--> Running transaction check
---> Package perl-Error.noarch 1:0.17010-1.el5 set to be updated
---> Package perl-Git.i386 0:1.7.4.1-1.el5 set to be updated
--> Finished Dependency Resolution
Dependencies Resolved
========================================================================================================
Package