300+ Red Hat Linux System Administration FAQs and Answers [Experienced / Freshers]

Red Hat Linux System Administration Interview Questions with Answers

Question: 1. How To Check The Uptime Of A Linux Server?

Answer:

Using uptime command we will decide how long a linux field has been walking , also uptime can be regarded by way of the pinnacle & w command.

Question: 2. How To Check Which Redhat Version Is Installed On Server?

Answer:

Use the command cat /and many others/redhat-launch , output of this command will tell you the redhat version.

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Question 3. How To Install Rpm Packages In Redhat & Centos Linux ?

Answer:

rpm and yum command are used to put in programs in redhat linux and CentOS.

Question: 4. How To Check The Ip Address Of Lan Card?

Answer:

Using ‘ifconfig’ & ‘ip deal with’ command we are able to decide the ip address of LAN Card.

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Question 5. How To Determine The Hostname Of A Linux Box?

Answer:

On typing the hostname command on terminal we will determine the hostname of a linux server.

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Question 6. How To Check The Default Gatway?

Answer:

Using ‘route -n’ command we will determine the default gateway in linux.

Question: 7. Which Command Is Used To Check The Kernel Version ?

Answer:

‘uname -r’

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Question 8. How To Check The Current Runlevel Of A Linux Box?

Answer:

‘who -r’ and ‘runlevel’ , each of these command are used to discover cutting-edge run stage.

Question: nine. What Is Initrd ?

Answer:

Initrd stands for preliminary ram disk , which contains the brief root filesystem and neccessary modules which helps in mounting the actual root filesystem in examine mode most effective.

Red Hat Linux Essentials Interview Questions
Question 10. What Is Bootloader?

Answer:

Bootloader is a program that boots the working machine and comes to a decision from which kernel OS will boot.

Question: 11. How To List Hidden Files From The Command Line?

Answer:

‘ls -a’

Technical Support Interview Questions
Question 12. What Is Soft Link?

Answer:

Soft link is a way to create quick cuts in linux. It is much like home windows brief reduce feature.

Network Technical Support Interview Questions
Question thirteen. How To Create A Blank File In Linux From Command Line ?

Answer:

Using the command ‘touch ’

Question: 14. What Is Run Level 2?

Answer:

Run level 2 is the multi-user mode without networking.

Question: 15. Why Linux Is Called Opensource?

Answer:

Because One can personalize the prevailing code and may redistribute it.

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Question sixteen. How To Check All The Installed Kernel Modules?

Answer:

Using the Command ‘lsmod’ we are able to see the established kernel modules.

Question: 17. What Is The Default Uid & Gid Of Root User?

Answer:

Default uid & gid of root user is 0.

Logical Volume Manager (Linux) Interview Questions
Question 18. How To Change The Password Of User From The Command Line?

Answer:

‘passwd ’

Linux Interview Questions
Question 19. What Is A Process?

Answer:

Any software in execution is referred to as a manner.

Question: 20. What Is Name Of First Process In Linux?

Answer:

‘init’ is the first manner in linux that’s commenced with the aid of kernel and whose pid is 1.

Red Hat cluster Interview Questions
Question 21. What Is The Difference Between Umask And Ulimit ?

Answer:

umask stands for ‘User file introduction masks’, which determines the settings of a mask that controls which report permissions are set for files and directories whilst they’re created. While ulimit is a linux constructed in command which affords control over the resources to be had to the shell and/or to approaches began by means of it.

You can restriction consumer to specific range by means of modifying /and many others/safety/limits.Conf at the equal time machine extensive settings can be up to date in /and so forth/sysctl.Conf

Question: 22. What Are The Run Levels In Linux And How To Change Them?

Answer:

A run degree is a kingdom of init and the complete device that defines what machine offerings are running and they may be diagnosed by numbers.There are 7 extraordinary run ranges gift (run level 0-6) in Linux device for one-of-a-kind cause. The descriptions are given under.

Zero: Halt System (To shutdown the gadget)
1: Single user mode
2: Basic multi person mode without NFS
three: Full multi consumer mode (textual content based)
four: unused
five: Multi person mode with Graphical User Interface
6: Reboot System

To alternate the run degree, edit the file “/and so forth/inittab” and alternate initdefault entry ( id:five:initdefault:). If we need to trade the run level at the fly, it can be performed the use of ‘init’ command.

For example: while we type ‘init 3′ in the commandline , this may flow the gadget from modern-day runlevel to runlevl three. Current degree can be indexed by means of typing the command ‘who -r’.

Question: 23. What Is The Functionality Of A Puppet Server?

Answer:

Puppet is an open-source and organization software for configuration control toll in UNIX like working device. Puppet is an IT automation software used to push configuration to its clients (puppet sellers) using code. Puppet code can do an expansion of duties from putting in new software program, to check report permissions, or updating person bills and masses of other duties.

Red Hat Satellite Interview Questions
Question 24. What Is Selinux?

Answer:

SELinux is an acronym for Security-more desirable Linux. It is an get admission to control implementation and security function for the Linux kernel. It is designed to defend the server in opposition to misconfigurations and/or compromised daemons. It positioned limits and instructs server daemons or programs what files they could access and what moves they are able to take by way of defining a security coverage.

Linux Embedded structures Interview Questions
Question 25. What Is Crontab And Explain The Fields In A Crontab ?

Answer:

The cron is a deamon that executes instructions at particular dates and times in linux. You can use this to time table sports, either as one-time events or as habitual tasks. Crontab is this system used to put in, deinstall or listing the tables used to force the cron daemon in a server. Each user will have their very own crontab, and although those are files in /var/spool/cron/crontabs, they’re not intended to be edited immediately. Here are few of the command line alternatives for crontab.

Crontab -e Edit your crontab record.
Crontab -l Show your crontab file.
Crontab -r Remove your crontab report.

Traditional cron layout consists of six fields separated with the aid of white spaces:

The format is defined in element beneath variety +—- Day of the Week (variety: 1-7, 1 status variety: 1-12)

variety: 1-31)

range: zero-23)

+———— Minute (range: 0-59)

Question: 26. What Are Inodes In Linux ? How To Find The Inode Associated With A File ?

Answer:

An inode is a data structure on a filesystem on Linux and other Unix-like operating systems that stores all of the statistics approximately a document except its call and its real information. When a document is created, it’s far assigned both a call and an inode range, that is an integer this is unique within the filesystem. Both the record names and their corresponding inode numbers are stored as entries in the directory that looks to the consumer to comprise the documents. The idea of inodes is especially vital to the healing of damaged filesystems. When components of the inode are misplaced, they seem inside the lost+located listing within the partition wherein they as soon as existed.

The following will show the name of each item within the current directory collectively with its inode quantity:

# ls -i

The avialble quantity inodes in a filesystem can be found the use of the underneath command :

# df -i

The other manner we can get the inode information of a report by way of using the stat commmand.

Usage : # stat

Example :

-sh-four.1$ stat note.Txt

File: `word.Txt’

Size: 4 Blocks: eight IO Block: 4096 regular report

Device: fd05h/64773d Inode: 8655235 Links: 1

Access: (0644/-rw-r–r–) Uid: (69548/nixuser) Gid: (25000/ UNKNOWN)

Access: 2014-06-29 15:27:fifty six.299214865 +0000

Modify: 2014-06-29 15:28:28.027093254 +0000

Change: 2014-06-29 15:28:28.027093254 +0000

Advanced Linux Interview Questions