[root@localhost ~]# yum -y install mariadb-server mariadb mariadb-devel Loaded plugins: fastestmirror, langpacks Existing lock /var/run/yum.pid: another copy is running as pid 4142. Another app is currently holding the yum lock; waiting for it to exit... The other application is: PackageKit Memory : 129 M RSS (541 MB VSZ) Started: Wed Jul 20 21:34:31 2016 - 13:59 ago State : Sleeping, pid: 4142 Another app is currently holding the yum lock; waiting for it to exit... The other application is: PackageKit Memory : 129 M RSS (541 MB VSZ) Started: Wed Jul 20 21:34:31 2016 - 14:01 ago State : Sleeping, pid: 4142 ^C Exiting on user cancel. [root@localhost ~]# rm -rf /run/yum.pid
小技巧：
通过以下命令找到yum.pid的具体路径，然后rm -rf掉。
find / -name yum.pid