使用centos时，使用yum安装软件，老是会遇到这种提示：
Existing lock /var/run/yum.pid: another copy is running as pid 3053. Another app is currently holding the yum lock; waiting for it to exit... The other application is: PackageKit Memory : 37 M RSS ( 82 MB VSZ) Started: Sun Jan 24 16:11:53 2010 - 14:44 ago State : Sleeping, pid: 3053
enabled=0
原文地址：http://blog.csdn.net/xuzhina/article/details/44037585
