输入命令:yum install gcc
提示:
Loaded plugins: fastestmirror, langpacks
Existing lock /var/run/yum.pid: another copy is running as pid 3535.
Another app is currently holding the yum lock; waiting for it to exit...
The other application is: PackageKit
Memory : 40 M RSS (515 MB VSZ)
Started: Thu Dec 17 20:11:06 2015 - 00:20 ago
State : Sleeping, pid: 3535
百度了一下，发现问题：
可能是系统自动升级正在运行，yum在锁定状态中。
可以通过强制关掉yum进程：
#rm -f /var/run/yum.pid
然后就可以使用yum了。
随后依次输入
yum -y install gcc
yum install make
-- 或者yum groupinstall "Development Tools"
成功