用yum安装软件提示的解决方法：

[root@centosf2 beauty]# yum install gcc

Loaded plugins: fastestmirror
Existing lock /var/run/yum.pid: another copy is running as pid 1479.
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: yum
    Memory :  55 M RSS (355 MB VSZ)
    Started: Thu Oct 30 12:40:56 2014 - 1:17:37 ago
    State  : Sleeping, pid: 1479
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: yum
    Memory :  55 M RSS (355 MB VSZ)
    Started: Thu Oct 30 12:40:56 2014 - 1:17:39 ago
    State  : Sleeping, pid: 1479
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: yum
    Memory :  55 M RSS (355 MB VSZ)
    Started: Thu Oct 30 12:40:56 2014 - 1:17:41 ago
    State  : Sleeping, pid: 1479

这是由于锁定了yum，使用rm -rf /var/run/yum.pid来解锁就OK了