After our previous post in this series, this fourth section will help you to explore next 5 tricky, advanced level questions generally asked by the system administration interview board to comprehend your ability to deal practical problems. By enrolling yourself for Linux courses you can have more of such questions and in turn can help you to get Linux certification. Here we present the last set of top 20 questions you are likely to be asked during Linux system administration interview with answers from professional experts. Q16. How is it possible to upgrade Kernel in Linux? An impossible task as one can never upgrade Linux Kernel, rather install the New Kernel using rpm command .If you try to upgrade it can turn your Linux box in a unbootable state. Q17. Define unmask and how you can set the umask permanently for a user? umusk means “ User file creation mask” and it determines the settings of a mask that controls which file permissions are set for files and directories the moment they are created. To set umusk permanently it has to be loaded in the correct profile that depends on the default shell of the user. Q18. What do you mean by daemons? Daemons are services which provide several functions that are generally not available under the base operating system .Its most important function is to listen for service request and also to act at the same time on requests. The service once executed, it is disconnected till further requests. Q19. How is it possible to use shortcut for along pathname? It is possible. By using TAB key, you can do this through a feature known as filename expansion. For instance if you have a path named /home/cowboy/worksheets directory, you need to type: /ho[tab]/cow[tab]/work[tab] .This will assume that the path is unique and the shell used by you supports this feature. Q20. What do you understand by nameless directory? It is the nameless base of the Linux file system. It serves as an attachment for all other files, directories, devices and even drives. By now you must be well prepared with the entire set of 20 questions. For more sign up for Linux courses. Best of luck!