用yum安装包有时候会提示

```
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: PackageKit
    Memory : 128 M RSS (439 MB VSZ)
    Started: Fri Aug 28 08:08:31 2015 - 48:25 ago
    State  : Sleeping, pid: 3462

```
解决方法：

```
rm -f /var/run/yum.pid
```
然后重新执行yum就可以了

永久禁止该错误

```
[root@oracle pluginconf.d]# cd /etc/yum/pluginconf.d/
[root@oracle pluginconf.d]# ls
product-id.conf  refresh-packagekit.conf  rhnplugin.conf  security.conf  subscription-manager.conf
[root@oracle pluginconf.d]# vim refresh-packagekit.conf
[main]
enabled=0  --将原来的1改成0即可