Technical troubleshooting and more

When trying to apply patch you may face this error the solution is described below. ERROR: bash-4.2$ ../opatch apply Oracle Interim Patch Installer version 12.2.0.1.5 Copyright (c) 2016, Oracle Corporation.  All rights reserved. Oracle Home       : /oracle/app/oracle/product/12.1.0 Central Inventory : /oracle/app/oracle/oraInventory    from           : /oracle/app/oracle/product/12.1.0/oraInst.loc OPatch version    : 12.2.0.1.5 OUI version       : 12.1.0.2.0 Log file location : /oracle/app/oracle/product/12.1.0/cfgtoollogs/opatch/opatch2016-07-27_16-27-44PM_1.log Verifying environment and performing prerequisite checks... Prerequisite check "CheckSystemCommandAvailable" failed. The details are: Missing command :fuser Prerequisite check "CheckSystemCommandAvailable" failed. The details are: Missing command :fuser Prerequisite ...