Linux FAQs - Advanced Questions and Answers

What is Linux and why is it so popular? - Linux is an operating system that uses UNIX like Operating system. However, unlike UNIX, Linux is an open source.......
What is LILO? - LILO is Linux Loader is a boot loader for Linux. It is used to load Linux into the memory and start the Operating system.......
Difference between home directory and working directory - Home directory is the default working directory when a user logs in. On the other hand, working directory is the user’s current directory......
Difference between internal and external commands - Internal commands are commands that are already loaded in the system. They can be executed any time and are independent.......
Linux static library and dynamic library - Static libraries are loaded when the program is compiled and dynamically-linked libraries are loaded......
LD_LIBRARY_PATH is an environment variable. It is used for debugging a new library or a non standard library......
What is the file server in Linux server? - File server is used for file sharing. It enables the processes required fro sharing. All the files can be stored......
What is NFS? What is its purpose? - NFS is Network File system. It is a file system used for sharing of files over a network.......
How do I send email with linux? - Email can be sent in Linux using the mail command........
RPM (Red Hat Package Manager) - RPM is a package managing system (collection of tools to manage software packages).......
What is Kernel? Explain the task it performs - Kernel is used in UNIX like systems and is considered to be the heart of the operating system.......
What is Linux Shell? What is Shell Script? - Linux shell is a user interface used for executing the commands........
What are Pipes? Explain use of pipes - A pipe is a chain of processes so that output of one process (stdout) is fed an input (stdin).......
Linux commands - Trap command: controls the action to be taken by the shell when a signal is received........
What is Stateless Linux server? What features it offers? - A stateless Linux server is a centralized server in which no state exists on the single workstations......
What does nslookup do? Explain its two modes - Nslookup is used to find details related to a Domain name server.......
What is Bash Shell? - Bash is a free shell for UNIX. It is the default shell for most UNIX systems.......
Network-Monitoring Tools in Linux - Network monitoring tools are used to monitor the network, systems present on the network, traffic etc........
How does the linux file system work? - Linux file structure is a tree like structure. It starts from the root directory, represented by '/', and then expands......
What are the process states in Linux? - Running, Interruptible, Uninterruptible, Stopped, Zombie.......
What is a zombie? - Zombie is a process state when the child dies before the parent process........
Process management in linux - System calls used for Process management.......
Describe initial process sequence while the system boots up - BIOS, Master Boot Record (MBR), LILO or GRUB, Kernel, init, Run Levels........
What is a shell? What are shell variables? - A shell us an interface to the user of any operating system........
Explain how the inode maps to data block of a file - There are 13 block addresses in inode.........
Explain some system calls used for process management - The following are the system calls:.......
Explain how to get/set an environment variable from a program - An environment variable can get using the function getenv()......
Describe how a parent and child process communicates each other - The inter communication between a child process and a parent process........
What is a Daemon? - Daemon is the short form for Disk and Execution Monitor......
What is 'ps' command for? - The shortage for “process status” is ps.......
How the Swapper works? - Moving the information from fast access memory and slow access memory and vice versa is known as swapping........
What is the difference between Swapping and Paging? - Swapping performs the whole process to transfer to the disk, where as paging.......
What is Expansion swap? - Expansion swap is a part of hard disk.........
What is Fork swap? - For creation of child process, fork() system call is invoked......
What are the requirements for a swapper to work? - The functionality of a swapper is on the scheduling priority which is highest........
What is ‘the principle of locality’? - The next most data item or instruction is the closest to the current data item or instruction.....
What is page fault? Its types - One of the critical parts of code in the Linux kernel....
Difference between the fork() and vfork() system call - fork: Both the parent and child share all of the page tables until any one of them does a write.........
What is BSS(Block Started by Symbol)? - UNIX linkers produce uninitialized data segments........
What is Page-Stealer process? - The pages that are eligible for swapping are found by the Page-Stealer’ and places........
Explain the phases of swapping a page from the memory - The phases of swapping a page from the memory are:.......
What is Demand Paging? - The process of mapping a large address space into a relatively small amount........
Difference between Fault Handlers and the Interrupt handlers - Fault handlers can sleep, where as interrupt handlers cannot........
What is validity fault? - Validity fault is the result of non setting of valid bits in main memory at the time of refererring a page by a process .........
What is protection fault? - Protection fault is a name of an error........
Explain how the Kernel handles both the page stealer and the fault handler - When the memory shortage occurs then the page stealer and fault handler thrashes........
What is ex and vi? Explain their purposes - vi – screen oriented visual editor.........
What is kill()? Explain its possible return values - kill() is a system call which stops a process.........
Explain the steps that a shell follows while processing a command - The sequence of executing commands by shell are as follows:.......
Difference between cmp and diff commands - Byte by byte comparision performed for two files comparision and displays the first mismatch byte.........
What is the use of ‘grep’ command? - Grep stands for regular expression. ‘grep’ command is used to find the patterns in a text file provided by the user.......
Difference between cat and more command - The file contents are displayed by ‘cat’ command.........
What is ‘du’ command? What is its use? - The du (disk usage) command is used to report the size of directory trees......
Explain the various prompts that are available in a UNIX system - UNIX supports 4 prompts - PS1: default prompt.......
Describe how the kernel differentiates device files and ordinary files - There are 2 device files. They are character device file and block device file........
How to switch to a super user status to gain privileges - The command ?su? is used to get super user status.......