Most Asked Linux Interview Questions

List of recent Linux Interview question asked from our students in different companies for “Entry Level Linux Administrator” profile.

These questions were asked in different companies from RHCE students. All aspiring Linux administrators make sure they know the answers of at least all these questions before appearing for any Linux Interview.

1. What is SSH? What is the default port number of SSH?

2. What is Linux SWAP space? How it is used?

3. What is booting Process in Linux?

4. What are the command used to kill and terminate the process in Linux?

5. How do you see routing table in Linux?

6. What is the difference between GREP and FIND command?

7. How to check PHYSICAL MEMORY size in Linux?

8. Command to check Linux system related information?

9. How do you monitor live process in Linux machine?

10. What is Telnet and port number of Telnet?

11. What is DNS?

12. What is DHCP and port number of DHCP?

13. What are default permissions set on file and directory on Linux?

14. What is HEAD and TAIL command?

15. What is name/path of configuration file of SAMBA?

16. What is IPtables in Linux?

17. Command to check memory related information?

18. How to check Internet Protocol address with local user login?

19. What is the difference between Router and Repeater?

20. What is the difference between TOP and PS command?

21. What is vmstat command?

22. What is RAID?

23. How do you see the memory usage?

24. How do you see the Linux system boot messages?

25. Do you know about OS Hardening?

26. What OS applications you know?

27. How do you change the gateway permanently?

28. What do you know about fencing in Clusters?

28. What is the difference between cp, scp, rsync?

29. How do you configure Apache with SSL?

30. How do you configure DHCP, NFS, FTP, SAMBA, APACHE & TOMCAT server?

31. How do you check for already installed packages using RPM?

32. Do you tar and untar?

33. What is the difference between tar and gunzip?

34. How much a file can be compressed?

35. How many fields are there in crontab?

36. How do you create a crontab file and how do you list the crontab?

37. If you have 200 log files, how will you search a particular file?

38. If I have 2 servers. I want to transfer server1 2GB data to server2 without causing any overhead on the server1 and on the network. It should be fast. Also server1 space is full and you cannot add any more overhead on it. What is the method?

39. I have some 50 servers, how will you apply a patch on all the 50 servers at one time and what is the Linux technology you will use to patch all the 50 servers at a time?

40. What is kernal panic & memory leak. Can you tell me where it happens and how it happens?

41. What is Linux?

42. What is DNS?

43. What is IP address?

44. Version of IP?

45. Difference between Windows & Linux?

46. Which command is used to see that what is user doing in his terminal?

47. Configuration of Samba server.

48. Explain booting process and grub.conf file?

49. Common commands for monitoring Linux .

50. NFS server configuration?

51. Difference between Layer 2 and Layer 3 devices?

52. How to configure two lan card in your eth0 port?

53. Difference between soft link and hard link?

54. What does these command do – vmstat, htop, grep?

55. How to find Linux OS current version OR Linux kernel current version?

56. Configure at least one server like Apache, LDAP, NFS, DHCP or SQUID?

57. How to check Linux system’s current used and remaining physical memory?

58. How to change the ownership of a file?

59. Can we used multiple IP in a single system, if yes, then how?

60. How to check Linux system performance & what is the use of top command?

61. Linux is which kind of operating System i.e. multi user or multi tasking or multi-processing?

62. What is the port number of these services- ftp, ssh, dns, http, https, telnet, smtp, ntp, mysql?

63. How to add printer to a Linux machine?

64. How to reset the root password in Linux, if root password is lost?

65. Who developed the kickstart in Linux?

66. Difference between Red Hat Linux and Ubuntu Linux?

67. Who created vi editor and can you run a command in vi editor?

68. How to find the process which is consuming the maximum memory of system?

69. Explain different parameter of top command like load division?

70. What is the core of Linux operating system?

71. What are different run levels of Linux operating system?

72. How to login via SSH to a another Linux system?

73. What is port number of MySQL?

74. How to check MySQL version in current Linux operating System?

75. How to login to MySQL in Linux OS?