linux interview questions and answers

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1. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers What is Linux Linux is, in simplest terms, an operating system. It is the software on a computer that enables applications and the computer operator to access the devices on the computer to perform desired functions What is LILO? LILO stands for  Li nux  Lo ader. LILO is Linux's boot loader which is used to boot up Linux. It can also be used to dual-boot or multi-boot different operating systems. INSTALLATION Which account is created when you install Linux ? Super user account   or the   root user account

2. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers KERNEL What is kernel ? The core of the Linux system is the  kernel . The kernel controls all of the hardware and software on the computer system, allocating hardware when necessary, and executing software when required.   What is Netfilter ? The Linux kernel’s network packet processing subsystem is  called Netfilter   What is  notification chains? The kernel’s many subsystems are heavily interdependent, so an event detected or generated by one of them could be of interest to others. To fulfill the need for interaction, Linux uses so-called  notification chains

3. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers LVM What do you mean by LVM? Logical Volume Manager( LVM ) allows administrators the flexibility to create logical disks that can be expanded dynamically as more disk space is required How to see the logical  volume and its sizes? #  lvs How to remove the LVM? #  umount   /dev/ vg_name / lv_name #  lvremove /dev/ vg_name / lv_name  

4. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers PARTED How can you display  the information about disk drive? # parted How can you l check free space on drive /dev/ sda with parted command? #parted /dev/ sda What is  the use of parted command?   Add  the partition View and change the existing partition  

5. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers FILE SYSTEM What is Swap Space? Swap space   in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space. Which partition is used for virtual memory by a Linux system? swap How   to   check the swap space? free -m What you mean  by linux   filesystem ? The file system is divided into many parts; the  filesystem with /bin , / lib , /etc , /dev , and a few others; a / usr file system with programs and unchanging data; / var filesystem with changing data   How to identified the files accessed  within 25 days?   #  find  /  -type f  - atime   -25  >  file_name.files   How to find out which file system running  on your linux server currently?   # df

6. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers USER & SECURITY What is Swap Space? Swap space   in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space. Which partition is used for virtual memory by a Linux system? swap How   to   check the swap space? free -m What is user? Linux is provided by  users  and  groups . Each user is associated with a unique positive integer called the  user ID  ( uid ). During login, the user provides a username and password to the  login  program   How to create  a user? #  adduser   user_name #   useradd   user_name   How to  set to expire the particular  user account? #  chage   -E   30/12/2016   user_name

7. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers DNS What is Swap Space? Swap space   in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space. Which partition is used for virtual memory by a Linux system? swap How   to   check the swap space? free -m What is DNS?   Domain N ame System (DN S)  is the system that associates hostnames with IP addresses   What does BIND Stands for ?  BIND stands for Berkeley Internet Name Domain   What is the role of DNS ? A DNS server, or name server, is used to resolve an IP address to a hostname 

8. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers TCP / IP NETWORKING What is Swap Space? Swap space   in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space. Which partition is used for virtual memory by a Linux system? swap How   to   check the swap space? free -m What is TCP? TCP is a connection - oriented communication protocol. It maintains the state of the connection at any given point of time   What is IP header? The IP header has fixed as well as optional fields. The fixed header is 20 bytes long and the rest is optional   How the packet  filtered within the ipchain ? Ip chains  filter incoming, outgoing, and the  forwarded packets  

9. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers IPTABLES & FIREWALL What is Swap Space? Swap space   in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space. Which partition is used for virtual memory by a Linux system? swap How   to   check the swap space? free -m What Is  Firewall?   A firewall is a hardened and trusted host that acts as a  choke point  among a group of networks What is iptables ? Iptables is a generic table structure that defines rules and commands as part of the netfilter  framework that facilitates Network Address Translation (NAT), packet filtering, and packet mangling in the Linux   What Is IP Filtering? IP filtering is simply a mechanism that decides which types of IP packets will be processed normally and which will be dropped or rejected

10. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers RAID What is Swap Space? Swap space   in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space. Which partition is used for virtual memory by a Linux system? swap How   to   check the swap space? free -m What is RAID? RAID means  Redundant Array of Independent Disks configuration to further protect against multiple failures   Does Linux Support Virtualized File Systems Like RAID? The most recent Linux kernels support software RAID, and they will work with RAID disk controllers   What is software RAID? Software RAID means that an array is managed by the kernel, rather than by specialized hardware

11. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers BACKUP & RECOVERY   What is Swap Space? Swap space   in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space. Which partition is used for virtual memory by a Linux system? swap How   to   check the swap space? free -m What is backup? Backing up, refers to the copying and archiving of computer data so it may be used to  restore  the original after a loss event   Why we need backup? Backups are needed in case a file or a group of files is lost. The reasons for losing files include . Hardware failure like disk breaking, accidentally deleting wrong file and  computer being stolen. Backups help in all the above situations.   What is simple  backup? The simplest means of making a backup is to use  tar  to archive all the files on the system or only those files in a set of specific directories

12. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers VCS   What is Swap Space? Swap space   in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space. Which partition is used for virtual memory by a Linux system? swap How   to   check the swap space? free -m What you mean by  VCS? Veritas Cluster Server  also known as  VCS  is a High-availability cluster software, for Unix, Linux and Microsoft Windows computer systems   What is the use of VCS Simulator? VCS Simulator enables you to simulate and test cluster configurations. Use VCS Simulator to view and modify service group and resource configurations and test failover behavior.   How to check the status of  VCS? #   hastatus – summ

13. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers APACHE What is apache server?   The  Apache HTTP Server , colloquially called  Apache   is the world's most used web server software How to check the version of Apache server ? rpm - qa | grep httpd   What is the main configuration file for Apache? httpd.conf

14. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers RPM What is ftp? The File Transfer Protocol (FTP) is a standard network protocol used to transfer computer files from one host to another host over a TCP-based network, such as the Internet.   What does vsftpd stands for? Vsftpd means very secure FTP daemon   What all are the default port for vsftpd server? Port numbers  20 & 21

15. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers SAMBA What is Samba? Samba is a suite of Unix applications that speak the SMB (Server Message Block) protocol. Many operating systems   What is SWAT? Samba Web Administration Tool  (SWAT) is used to simplify administration and configuration of Samba   How  to install samba? #     yum -y install samba  

16. Linux Administration For more details : - http:// raju-linux-admin.blogspot.in Interview Questions and Answers Thank you