2021: Top 99 Linux Interview Question

Linux is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged in a Linux distribution.

Here is the list of top 99 Linux interview question

  1. Which file is responsible for forwarding (dns) and what’s meaning of MX,ptr record?
  2. What is use of xargs with find command?
  3. What is use of lsof command?
  4. What is the use of spf record & domain keys in mail server?
  5. What is the use of acls in linux and how to implement acls?
  6. What is the use of ‘exec’ & ‘ok’ option in find command?
  7. What is the use of .netrc file in linux?
  8. What is the term “network bonding” and what are different levels of bonding?
  9. What is the role of boot loader(grub)?
  10. What is the role of %pre & %post in kickstart?
  11. What is the role fencing in redhat cluster?
  12. What is the role and size of mbr?
  13. What is the process to scan newly assigned san’s lun on linux server without rebooting?
  14. What is the process to create logical volume manager (LVM) of newly created LUN?
  15. What is the main boot sequence of a linux server?
  16. What is the limitation of fdisk command & where to use parted command?
  17. What is the function of syslog?
  18. What is the format of /etc/fstab file?
  19. What is the difference between yast & yast2 command?
  20. What is the difference between useradd and adduser?
  21. What is the difference between -u & -f option in rpm command?
  22. What is the difference between rhn and spacewalk?
  23. What is the basic format of nfs mount?
  24. What is sticky bit and where to use?
  25. What is static and dynamic route in Linux?
  26. What is ssh port forwarding?
  27. What is set uid and gid?
  28. What is role of $0, $? And $# in shell scripting?
  29. What is raid & what are different types of raid levels?
  30. What is power path overview with software/driver installation on linux servers?
  31. What is meaning of “no_root_squash” in nfs ?
  32. What is lvm snapshot and use of lvm snapshot?
  33. What is lds certificate?
  34. What is journaling in linux ?
  35. What is hard disk driver or hard disk module, what is the difference between both. Explain.
  36. What is grub and what are its different stages?
  37. What is difference between sar and vmstat?
  38. What is difference between nfs3 & nfs4?
  39. What is anacron and where we can use anacron?
  40. What daemons need to run for nfs client?
  41. What are zombie processes and how to check zombie processes?
  42. What are the different states of a process in linux/unix?
  43. What are the different fields of crontab file & cron log file?
  44. What are the default ports used for smtp, ftp, ssh & samba service?
  45. What are logical steps for pxe server setup in linux?
  46. What are different types of file system in linux difference and what is the difference between ext2 & ext3 and ext4 file system?
  47. What are different components of postfix mail server?
  48. Is there a way to check the current system kernel for 32-bit kernel vs. 64-bit kernel?
  49. Is it possible to boot the system without /boot partition or deleted /boot partition?
  50. In linux boot sequence lvm initialize is happen on which stage?
  51. How you check the bottle neck of slow server ?
  52. How will you use trap and shift command in unix ?
  53. How will you patch older kernel version in linux machine ?
  54. How will you load pam module in linux machine?
  55. How will you get module / driver information in linux ?
  56. How will you differentiate defunct and running processes in linux ?
  57. How will you deactivate mouse in rhel and which service is resposible for that ?
  58. How will you check last week accessed files ?
  59. How will supply/reset password for 50 user without typing password again & again ?
  60. How we can get get the wwn number of hba card installed in linux
  61. How to work in 2 different files with vi editor, how to copy paste & cut in multiple files ?
  62. How to share a linux resource or storage on microsoft windows machine?
  63. How to set the date in ist format from the command line ?
  64. How to set grub boot loader password ?
  65. How to set default gateway in different ways ?
  66. How to run job in background ?
  67. How to run a particular script in runlevel 3 ?
  68. How to resolve if authentication failure (incorrect password ) ?
  69. How to re-size the file system ?
  70. How to reset the grub password and root password in linux ?
  71. How to reset failed login counts in linux ?
  72. How to recover deleted lvm partitions in linux ?
  73. How to preserve the permission on tar backup ?
  74. How to patch linux servers using spacewalk ?
  75. How to mount iso file in linux ?
  76. How to integrate linux servers with microsoft active directory ?
  77. How to increase size of swap in linux ?
  78. How to gracefully shutdown two node linux cluster in case of planned power outage ?
  79. How to find the tape device name in linux ?
  80. How to find the mx record of a domain from the command line ?
  81. How to create yum repository locally ?
  82. How to check yum repositry information & clear yum cache in linux ?
  83. How to check which nfs share is mounted ?
  84. How to check whether oracle is installed or not in unix ?
  85. How to check what are the driver installed in system ?
  86. How to check the version of package ?
  87. How to check nfs version and release ?
  88. How to check active ports in linux ?
  89. How to change the complexity of password ?
  90. How to change run level with in linux ?
  91. How to change network interface name ifcfg-eth0 to ifcfg-nic0
  92. How to calculate free size from free pe mentioned in vg display ?
  93. Give one exmaple of suid, sgid and sticky bit ?
  94. From where the command ‘rpm -qa’ find the installed packages ?
  95. Differnce b/w automount fs and nfs
  96. Difference between tar,cpio & dd backup ?
  97. Difference between super block and data block ?
  98. Difference between lvm1 and lvm2 ?
  99. If we have a file info.txt, how you will give permission as below :     Group name – admin, write only,              Users – tom & jerry only read
    users – sany ,  read write execute.
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