Top 100 Linux Interview Questions


Q:1 What is the boot sequence of a linux server ?

Q:2 What is Hard disk driver or Hard disk module, are they different or same. Explain.

Q:3 How you will get the WWN number of HBA card installed in Linux

Q:4 How to check RHEL Version ?

Q:5 What is network bonding and different levels of bonding ?

Q:6 How to share a linux resource on windows machine ?

Q:7 How to scan newly assigned SAN’S LUN on Linux server without rebooting ?

Q:8 How to reset grub passwd and root passwd in linux ?

Q:9 What is journaling in linux ?

Q:10 What is difference between ext2 & ext3 and ext4 file system ?

Q:11 What are the steps to create LVM of newly created LUN ?

Q:12 How to see the tape device name in linux ?

Q:12 Power path Overview with software/driver installation on Linux servers ?

Q:13 What is RAID & different types of RAID levels ?

Q:14 What are the default ports used for smtp , ftp, ssh & samba ?

Q:15 How to calculate free size from free PE mentioned in VG Display ?

Q:16 LVM initialize on which stage in boot sequence ?

Q:17 What Grub and its different stages ?

Q:18 If we have a File data.txt, How you will give permission as below
Group Name – finance, write only
Users – tom & jack only read
Users – bond , read write execute.

Q:19 How to change network interface name ifcfg-eth0 to ifcfg-nic0

Q:20 How to re-size the file system ?

Q:21 How to preserve the permission on tar backup ?

Q:22 How to set default gateway in different ways ?

Q:24 How to work in 2 different files with vi editor, How to copy paste & cut in multiple files ?

Q:25 Difference between tar,cpio & dd backup ?

Q:26 How to increase size of swap in linux ?

Q:27 How to run a particular script in runlevel 3 ?

Q:28 What is meaning of “no_root_squash” in nfs ?

Q:29 What daemons run on nfs client ?

Q:30 How to check what are the driver installed in system ?

Q:31 What is the format /etc/fstab file ?

Q:32 From where the command ‘rpm -qa’ find the installed packages ?

Q:33 What is the function of syslog ?

Q:34 How you check the bottle neck of slow server ?

Q:35 What is the basic format of NFS mount ?

Q:36 Differnce b/w automount FS and NFS

Q:37 What is the role of boot loader(GRUB) Stage 1.5 ?

Q:38 Difference between super block and data block ?

Q:39 How to check the version of package ?

Q:40 What is Set UID and GID ?

Q:41 What is sticky bit and where to use ?

Q:42 Difference between LVM1 and LVM2 ?

Q:43 What is role of $0, $? and $# in shell scripting ?

Q:44 How to find the MX record of a domain from the command line ?

Q:45 What is the limitation of fdisk command & where to use parted command ?

Q:46 What are Logical steps for PXE Server setup in linux ?

Q:47 What is the role of %pre & %post in kickstart ?

Q:48 What are the different fields of crontab file & cron log file ?

Q:49 what is the difference between -U & -F option in rpm command ?

Q:50 How will supply/Reset password for 50 user without typing password again & again ?

Q:51 How will you get Module / Driver Information in linux ?

Q:52 How to check active ports in linux ?

Q:53 What is difference between sar and vmstat ?

Q:54 is it possible to boot the system without /boot partition OR deleted /boot partition ?

Q:55 How to change the complexity of password ?

Q:56 How to resolve if authentication failure (incorrect password ) ?

Q:57 How to change run level with in linux ?

Q:58 How will you load PAM module ?

Q:59 Is there a way to check the current system kernel for 32-bit kernel vs. 64-bit kernel?

Q:60 which file is responsible for forwarding (DNS) and what’s meaning of MX,PTR record ?

Q:61 What are Zombie process and how to check Zombie Processes ?

Q:62 How will you differentiate defunct and running processes in linux ?

Q:63 How to run job in background ?

Q:64 What is anacron & where to use anacron ?

Q:65 What is the role and size of MBR ?

Q:66 How to set grub boot loader password ?

Q:67 How to set the date in IST FORMAT from the command line ?

Q:68 How to check nfs version and release ?

Q:69 what is static and dynamic route in linux ?

Q:70 How to check whether oracle is installed or not in unix ?

Q:71 How to check which nfs share is mounted ?

Q:72 How to mount ISO file in linux ?

Q:73 what is LDS certificate ?

Q:74 How will you patch older kernel version in Linux machine ?

Q:75 What is the difference between yast & yast2 command ?

Q:76 How will you deactivate mouse in RHEL and which service is resposible for that ?

Q:77 What is ssh port forwarding ?

Q:78 How to patch linux servers using spacewalk ?

Q:79 What is the difference between RHN and Spacewalk ?

Q:80 How to recover deleted LVM partitions in linux ?

Q:81 How will you use trap and shift command in unix ?

Q:82 What are different components of Postfix Mail Server ?

Q:83 What is the use of SPF record & Domain Keys in mail server ?

Q:84 What is difference between NFS3 & NFS4 ?

Q:85 What is use of lsof command ?

Q:86 How will you check last week accessed files ?

Q:87 what is the use of ‘exec’ & ‘ok’ option in find command ?

Q:88 Give one exmaple of suid, sgid and Sticky bit ?

Q:89 How to reset failed login counts in linux ?

Q:90 What is the use of .netrc file in linux ?

Q:91 How to integrate Linux Servers with Microsoft Active Directory ?

Q:92 What is use of xargs with find command ?

Q:93 What are the different states of a process in linux/unix ?

Q:94 What is the use of ACLs in linux and how to implement ACLs ?

Q:95 What is the difference between useradd and adduser ?

Q:96 What is LVM Snapshot and use of lvm snapshot ?

Q:97 How to check yum repositry information & clear yum cache in linux ?

Q:98 How to create yum repository locally ?

Q:99 What is the role fencing in redhat cluster ?

Q:100 How to gracefully shutdown two node linux cluster in case of planned power outage ?



  1. With Linux, lsmod can provide a list of modules and modinfo can give you a description of a module. If you get descriptions of all of the modules, you will see that most are drivers. But not all. If you make a list of the drivers that are modules you will be missing some drivers. That’s because some drivers are permanently built into the kernel without being encapsulated as a module.

    A driver talks to hardware or pretends to talk to hardware. Device files like /dev/tty or /dev/null exist so your program can interface with a driver.

    A module is a piece of a kernel that can be optionally loaded into the kernel.