Linux System Administrator Interview Questions (2023)

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Red Hat Linux System Administration Interview Questions 2023
Senior Linux Administrator Interview Questions & Answers

Red Hat Linux System Administration Interview Questions 2023

Here are some Red Hat Linux System Administrator level interview questions & answers or advanced level with frequently ask this question.

Linux or Unix Level 2 Interview Questions

Q 1. Explain the work Ctrl+Alt+Del key combination on the Linux operating system?

Ans: – The work of Ctrl+Alt+Del key combination in Linux operating system is same as is Windows to restart the system.

Q 2. Which are the different modes of VI/ VIM editor?

Ans: – There are 3 modes of VI/ VIM editor –

• Regular / Command mode: –
This mode helps to run commands, it is default mode of Vim.

• Insert / Edit mode: –
This mode helps to delete/ write text.

• Ex / Extended mode: –
This mode helps to execute commands. It helps to overwrite the content or saving the content.

Q 3. What is Link? What are the types of Link?

Ans: – To increase the availability of a location we need to create a Link. It is 2 type –

1) Hard Link: –
It is a mirror image of the source.
It’s consumed some space or source.
It’s inode no. is a same as source.
Its source is deleted we can get the whole data from this link.
It is limited on that drive only.

2) Soft/ Symbolic Link: –
It is a shortcut of the source.
It is consumed small amount spaces source (necligable).
It’s inode no. is different with source.
Its source is deleted we cannot get data from this link.
It can create in anywhere.

Q 4. What is the main different between Hard Link & Soft Link?

Ans: – Hard Link is only created in Folder but Soft Link is created in File or Folder.

Q 5. What is ”grep” command?

Ans: – Grep stands for Global Regular Expression Print. The grep command is used o search for a text in a file by pattern matching based on a regular expression.

Q 6. Explain the ”ls” command in Linux?

Ans: – Ls stands for long listing. The ls command is used to list the file in a specific directory.

Q 7. Why is the “tar” command used in Linux?

Ans: – The tar command is used to Backup & Restore backup a file.

Q 8. What is command for zip(compress) & unzip(uncompress) files?

Ans: – gzip – Compress File.
gunzip – Uncompress File.

Q 9. How to copy a file in Linux?

Ans: – You can use the CP command to copy a file in Linux.
Syntax – $ cp

Q 10. How would you create a text file without opening it?

Ans: – The “touch” command can be used to create a text file without opening it, the touch command will create an empty file.
Syntax – $ touch

Senior Linux Administrator Interview Questions & Answers

Q 11. What is the used ”cat” command in Linux?

Ans: – “Cat” command to create/ see a file in Linux.
Syntax – #cat

Q 12. What is the different between creating a file in “cat” and in “touch” command?

Ans: – “Cat” command creates a file and we can save some data inside the file but “touch” command by default will create a blank file.

Q 13. What is used ”mkdir” command in Linux?

Ans: – Create a directory or multiple directories.

Q 14. How would you delete a directory in Linux?

Ans: – “rmdir”
Syntax – # rmdir
“rm -rf”
Syntax – # rm -rf
The command “rm -rf” should be used carefully because it will delete all the data without any warnings.

Q 15. What are command would you schedule a task in Linux?

Ans: – There are 2 commands to schedule tasks in Linux – “Cron” & “at”.

Q 16. How do you look at the contents of a file name sample .z?

Ans: – The .z extension means that the file has been compressed. To look at the contents of the compressed file, you can use the zcat command.
Syntax – $ zcat sample .z

Q 17. Which command is the used of rename a file?

Ans: – ”mv” command.

Q 18. Is Linux operating system is the virus-free?

Ans: – No, there is no operating system till date is virus-free, but Linux is known to have less fewer of viruses.

Q 19. Which partition stores the system configuration files in Linux system?

Ans: – /stc partition.

Q 20. Why do developers use MD5 option?

Ans: – MD5 is an encryption method, so it is used to encrypt the password before saving.

Q 21. What is LVM?

Ans: – LVM stands for Logical Volume Manager. It is a store management device. LVM can attach memory from different locations. Users can create, resize and delete LVM partitions. LVM is used to gather existing storage devices into the group and allocate logical units.

Q 22. What is PV, VG & LV?

Ans: –

PV: –
It’s full from Physical Volume.
It is a array of drive.
It’s no name.
In one machine one PV.

VG: –
It’s full from Volume Group.
It must have unique name.
Every VG will ask as a Individual Logical Disk.
We cannot create more than one VG in a single system.

LV: –
It’s full from Logical Volume.
It is a Logical Drive.
We can create in from VG.
We can expend it.
We can reduce it but file system is ext.
We can take snapshot to recover data.
We can recover data from deleted LVM.

Q 23. Explain in PE?

Ans: –
It’s full from Physical Extension.
In LVM default size of PE is 4 MB.
In LVM single PE maximum size 64 MB.
In RHEL 6 in maximum PE size is (65536 in LVM = 65536*4 MB)= 256 MB.

Q 24. What is the different between ext4 & xfs file system?

Ans: –

It is Fourth version of extended file system.Xfs is extension of extent file system (Default in RHEL 7).
Its maximum file size is 17.6 TB.Its maximum file size is 8 exbibytes (EB).
Maximum volume or partition size is 1 EB.Maximum volume or partition size is 8 EB.
It supports journaling file system. Does not support Transparent encryption and data deduplication.It supports journaling file system, transparent
encryption and data deduplication. Does not support Transparent compression.

Q 25. What is Umask?

Ans: – Umask stands for User Mask or User File Creation Mask. It is a command that determines the settings that control how to file permission is set on newly created files.

Q 26. What is the default value of Umask?

Ans: – 022.

Q 27. How to you create a new user without logging on as a root user?

Ans: – Using the ”Su” command.

Q 28. Which command would you create a file system on a new hard drive?

Ans: – The ”mkfs” command.

Q 29. Which file is used to automatically mount file system?

Ans: – Fstab file.

Q 30. What is the role of Kernel?

Ans: – It interacts with hardware and most of the tasks like memory management, task scheduling and file management.

Q 31. What is the name of command to change the password?

Ans: – ”Passwd”.

Q 32. Name of the command which can be used to shut down the system?

Ans: – ”shutdown”.

Q 33. Name a command which can be used to restart the machine?

Ans: – ”reboot”.

Q 34. What is hidden file?

Ans: – A file/ directory name beginning with .(dot) is considered as hidden file.

Q 35. What is Zombie process?

Ans: – The process is dead but has not been removed from the process table.

Q 36. Which command can be used to know the terminal type?

Ans: – tty.

Q 37. What is full form of tty?

Ans: – Teletype but it’s more popularly known as Terminal.

Q 38. How many virtual console or tty have in Linux?

Ans: – 6 virtual console by default, in addition to already existing GUI.

Q 39. How to open Linux terminal?

Ans: – Open menu – navigate to Application and select Utilities and click on option terminal.
or, press key – Alt+F2 – type gnome-terminal and enter.

Q 40. What is Linux Terminal?

Ans: – A terminal is an emulated console of Linux. It is a graphical program such as gnome-terminal.

Linux Interview Questions and Answers for Experienced

Q 41. What is Kerberos used for?

Ans: – Kerberos is used for secure network login.

Q 42. Different between Home directory and Working Directory?

Ans: – Home directory is the default working directory when a user log in. On the other hand, the working directory is the user’s current directory.

Q 43. What is the difference between Soft Link & Hard Link?

Ans: – It is a method to create shortcuts in Linux. It is very similar to the Windows shortcut feature. A symbolic Link or Soft Link is a link to another name in the file system. But a Hard Link has been made the link is to the inode. So, renaming or moving or even deleting the actual file, will not affect the Hard Link as it links directly to the underlying inode, but it will surely delete the Soft Link.

Q 44. What is the name of the first process that runs in Linux?

Ans: – init.

Q 45. In which directory by default user home directories are created?

Ans: – /home.

Q 46. What is the default working directory of an administrator?

Ans: – /root.

Q 47. What is the login name of the administrator?

Ans: – root.

Q 48. What is the mean of ”/”, ”root” & ”/root”?

Ans: –
”/” – Super User.
”root” – Administrator.
”/root” – Home directory of an administrator.

Q 49. How to Upgrade the Kernel in Linux?

Ans: – We should never upgrade Linux Kernel, always install the new Kernel using rpm command because upgrading a Kernel can make your Linux box in an unbootable state.

Q 50. Which one is the default sticky bit directory?

Ans: – /tmp.

Q 51. What is the hexadecimal code no. for LVM?

Ans: – 8e.

Q 52. What are the two types of mount in Linux?

Ans: – Temporary mount & Permanent mount.

Q 53. What is the inbuilt firewall in Linux?

Ans: – IP tables, SELinux, TC PWrappers.

Q 54. What is the command to check SELinux status?

Ans: – “Getenforce”.

Q 55. How can I view hidden files in a system?

Ans: – ”ls -a” command.

Q 56. How can I give all permission ta a user?

Ans: – Use the “Chmod” command to give all read, write and execute permission to a user.
Syntax – chmod 777

Q 57. What is used Pipe command?

Ans: – Pipe symbol interlinks two commands. It stores the output of the first command and gives in to the second command.

Q 58. What is Init?

Ans: – Init checks the file /etc/inittab and decides the run level. There are seven run levels available from 0-6. It will identify the default init level and will load the program.

Q 59. What is the difference between “rm” and “rm –r”?

Ans: – “rm” command is used to delete all the files while “rm –r” command is used to delete all the files in a directory and also in subdirectories.

Q 60. What is netstat command used in Linux?

Ans: – netstat command in Linux shows the network status. This netstat command shows network ports in use and their incoming connections.

Red Hat Linux System Administration Interview Questions with Answers PDF Download

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