Linux Interview Questions And Answers | Linux Admin Interview Questions | Intellipaat

[Music] hello everyone welcome to this session on linux interview questions linux is probably the most used operating system in today's world any production system that you talk about 80 or 90 chances are there that they will be using the linux operating system so today in this session we have basically collated some of the most asked linux interview questions that you can come across while you're sitting in your next interview so let's get started now we have divided these interview questions into three sections that is beginner intermediate and then expert and we have basically collated 10 questions each in all of these sections but before we move on guys if you haven't already please subscribe to the intellipart channel and click on that bell icon to never miss out on any updates from us right so let's go ahead and get started with the first section which is the beginner section let's start off with the first question which is the most simplest question of all comparing linux with windows so we are comparing it in three criterias so the type of os linux is open source anybody could use it you can download it and you can even make changes to the kernel's code but you cannot do that in windows because windows is the proprietary operating system you can buy it and install it and you'll have to activate it by giving money so you'll have to give money to microsoft for the activated version of windows in linux it's completely open source customization linux can be customized as i told you you can change the code however you want you can make the changes to the kernel but you're all by yourself you can you can get the code online so that's why it's open source and really popular and also in windows it cannot be changed because it's completely owned by microsoft security is amazing linux but in windows you'll have to have a good antivirus software even if you have a good antivirus software there will be some kind of a malware which slips into your system and that might cause damage but in linux security is amazing there is not many chances of viruses getting into linux because yeah so there is no chance of virus is getting into linux but in windows there is a lot of security issues existing already and if you use windows defender or if you use any security tool any antivirus tool again there might be some security issues if you do not follow certain steps so the thing you'll have to understand is as an operating system linux is better than windows windows is better in the gui part than linux but linux is more to the customization side if you're a developer or if you're working with computers a lot then linux is the uh like go to operating system next question is what is lilo so lilo is short for linux loader while you load into your system if it is just a windows system then it gets directly logged into the windows system if it is a linux system it directly gets logged into the linux system but if you have a boot menu where you have dual booted your system with linux as well as windows in that case what will happen is you will get a lilo boot menu so linux loader boot menu very left choose on what operating system should be booted right now so linux loader is a boot loader for linux it is used to load linux into memory and start the operating system lilo can be configured to boot other operating systems as well so you can configure it to boot linux windows or any other type of linux operating system you need lilo is also a code snippet that loads pc buyers into the main memory at the time of starting the computer system so basically when you switch on your computer a code basically runs in the background to start of the operating system so that's why at the beginning it shows some loading icons then it shows you some menus and then it goes into the operating system because before opening or loading the operating system there is a step before which is basically the code snippet which runs to start off your operating system so basically the linux loader handles these tasks it locates the kernel of linux so that once it locates the kernel of linux only then you can basically enter the operating system then it identifies other supporting programs and loading them in memory so basically once the linux kernel is on you'll also have the other linux programs and utilities so all those applications and memory should be loaded once that is loaded the kernel will start and you can login into your operating system and start using it so this is linux loader coming to the third question suppose you wish to print a file draft with 60 lines on a page what command do you use so basically the command for this purpose is pr minus l 60 draft so now the default page length when using pr 66 lines you will have to use the l command to basically reduce the length to 60 so there is a file called draft and you want to print the first 60 lines on the page and you go to the command pr and if you want to uh like reduce the number of lines you'll have to use the my l command that's minus l and put the number of lines because the default number is 66 the fourth question what is ld underscore library underscore path what is ld library path it is an environment variable used for debugging a new library or a non-standard library basically a library which you install into your linux system it can be a new one or it can be a non-standard library which was created by some other user it is also used to identify the directories that need to be searched for in order to do this the path to search for the directories needs to be specified the variable can be set using the following command that is satan b hyphen ld library path minus minus dollar path so this is basically used to search for the shared objects or dynamic libraries by the operating system for extendable functionality at the runtime so basically this particular command chooses the library's path and with this path you can basically run that library whenever you want it to run so that's what they are mentioning in the last sentence it is used to search for shared objects or dynamic libraries so the library which you installed by the operating system for extendable functionality at the runtime so while you are running that certain task to search for that particular library which is needed to run the task so that's why you need ld library path it basically searches for the library you need gets the path name and uses it to execute it at runtime now the fifth question name a service that you should disable which acts both as web and ftp servers on a linux server so web in the sense http or https and ftp servers so you have to stop service which basically stops both of them so there is a service like that it's called finger service so the finger service should be disabled on a linux server because the remote user can get important information about the system by using this command basically there is a linux server you are using it you are the let's say the admin or the super user and your system is also used by multiple uh users who are using it remotely from their own pcs in that case you can use the finger service command to get all the information about them so basically we can get their login name their full name and possibly other details as well so you can get into their system and you can get possibly other details about the user so this is why this should be disabled on a linux server because it acts as both a web and ftp servers that basically means it also shows the web pages if you want to run also it can get files it can transfer files from other servers to your server or your server to other servers so that's why it has to be stopped and that service is called the finger service and the main reason it has to be stopped is because it can get important information about the remote users from your pc so that has to be stopped now what does salt provide where are the star logs stored now star is basically a command now let's look what command it is in linux this r command collects reports or saves system activity information and it serves to log and evaluate a variety of information regarding system activity so sar is basically a command which records system activity and with performance problems sars also permits retroactive analysis of load values for various subsystems so basically it checks out the system activity also it checks out cpus memory disks interrupts network interfaces so it checks all of this it basically has the value of all of this and the star command is basically used for this if cpu is near to 100 the sampled workload is considered to be cpu bond so let's say there is a load running on your server and if the cpu goes to 100 that basically means the workload you are running basically takes up a lot of cpu not memory or other things but it is cpu bound so that's exactly what sar does checks out system activity information and also all the other required information about cpus memory disks interrupts network interfaces and so on like devices and next question was where are the star logs stored so to check out all of this activity information you will have to go to the slash var slash log slash sa slash sa dd file so inside uh var slash log slash sa there is a a folder or a file called sadd and you'll have to use that file to check out the slots so all the log files will be stored over there by default the log files are stored over here where the dd parameter indicates the current date so you can see over here so var log slash sa inside this folder you have essay and you will have the current date over here so this is what depicts the current log files okay so this is what star provides and this is where this sar log files are stored next question is how to check memory stats and cpu stats as a linux admin so there is a command called free and this is a command called vm stat so now we can display the physical and virtual memory statistics respectively with the help of star command we can see the cpu utilization and other stats so sar does not need to be run manually it already runs in the background you just have to run the vm stat or other commands and star logs will be fetched and you will be given the information over here you can see they have also provided cpu information they've also provided memory information so they provide system information input output information so now they've asked this can we check memory and cpu stats yes we can check we can just use the vm stat command hyphen a and it will give you the free memory so if you use free memory it only if you use a free command it only shows the free memory uh it does not show the cpu of the system but if you want to check both at the same time you can use vmstat and it will show all the details over here and the linux admin can use this next how to reduce or shrink the size of the lvm partition so now lvm is basically logical volume manager where you can manage all the sizes of the disks so now uh they've asked us how to reduce it so now let's check out the steps so here are the logical steps to do that first you unmount the file system using the unmount command or the umount command so you there won't be an n you can use the umount command or the unmount command next is the resize to file system command so now you use this resize to file system command to change the size of the logical volume partition so there is only one disk with multiple logical partitions for example in your windows system you might have d drive and c drive but they are not actually separate disks inside your pc or inside your cpu but they are a single disk which which are separated logically by the system so like that you can also separate in linux so to resize one of your logical volumes you'll have to use the resize to fs command so resize to fs slash dev mapper slash my vg hyphen my lv so this is the logical volume name so device inside device you can find all the logical volume devices so now they are changing it to 10 gigs and then you'll have to use lv reduce command to reduce the volume to 10 gigs so over here lv reduce minus capital l or hyphen capital l 10 gigs 10 g and the same location so this is to resize it and this is to reduce the size of the volume so this way we can reduce the size of the lvm partition and fix the size of the file system to 10 gb so if you want to make it 30 gb you'll just have to change the values over here if you want to make it to 25 gb again only the values and also the uh logical volume name will be different in your pc in your linux system so you'll have to check that out and insert the correct address over here otherwise it won't work coming to the ninth question below is a list of we are sorry what are the different modes of network bonding in linux below is the list of various modes you use in network bonding so now network bonding is basically uh combining multiple network interfaces together so check out what are network interfaces before looking at this question okay so now there are multiple options first one is balance minus rr this is basically for round robin or zero the round robin mode for fault tolerance and load balancing we can use the round robin way and the mode is 0 or balance minus rr next is the active backup mode for fault tolerance which is set to number one and coming at number two our balance hyphen xor uh sets an xor mode for fault tolerance and load balancing then fourth broadcast or three so it's a broadcast mode for fault tolerance all transmissions are sent on all these slave interfaces so all the slave interfaces in the sense there will be a master network interface which is connected with multiple network interfaces and all the transmissions will be sent to all of them then eight not two point three eighty or four so it basically sets an ieee 802.380 dynamic link aggregation mode and creates aggregation groups that share the same speed and duplex settings which basically means when you combine multiple network interfaces all of those network interfaces will share the same speed and will share the same duplex settings that basically means all the transmission whatever happens through these network interfaces will have this same speed will not change next comes number five or balance tlb so this is called transmit load balancing it sets up transmit load balancing for fault tolerance and load balancing and finally balance alb which sets up uh active load balancing mode for fault tolerance and load balancing so these are the seven different modes which can be used in network bonding so network bounding as i told you it basically is combining or joining together multiple network interfaces so understand that if you do not know about this question only then you can understand what is going on over here finally the tenth basic question is how to check and verify the status of the bond interface so bond interface basically means the same as network bonding once you bonded it it's called bond interface so now using the following command we can check which mode is enabled and what lan cards are used in this bond so cat slash proc slash net slash bonding so this is the normal path which you'll have to look in your linux system to find out all the bonds available so you can name the bond accordingly over here there's a bond called zero so in this example we have a single bond interface however we can have multiple bond interfaces as well bond one bond two so you can have multiple bond interfaces within the same location so to check and verify if a bond interface is available in your linux system you'll have to go to this particular address that is uh proc net bonding slash bond zero if there is one zero or bond one or bond two available in this inside that your bond interface basically is available and it is verified okay it's next let's move on to the intermediate interview questions so the first question is how can you enhance the security of the password file in linux so there is a password file called slash etc slash password in your linux file system and so you'll have to uh they're asking you how to make this even more secure it isn't a test file named etc password that linux usually keeps its user account details including one-way encrypted passwords however this file can be accessed with the help of different tools which might throw security issues basically even though this file has one way encryption you can use certain tools and people can easily get the details out of this file if they get the access to the file so to minimize the risk of that happening we should make sure you use the shadow password format that saves the account details in a regular etc password file as in the traditional method but with the password stored as a single x character that is it is not the original password that is actually stored in this file meanwhile a second file so there are two files basically it's a shadow file this file replicates uh people will think this has the password but the second file which is the shadow file etc shadow will actually have the encrypted password along with the other relevant in information so such as account or password expiration date most importantly the later file is readable only by the root account and thus it minimizes the security risk that basically means the first file etc password can be read by any user on the system but the etc shadow file can be only read by the administrator or the root account so basically nobody else can access it and it minimizes the risk of your password going to another person's hand and this is how shadow password format works you have two files etc password etc shadow edc password has a single character x as your password but epc shadow has all the details and only the root account can access it the 12th question is what command can you use to make a tape archive file of slash home directory so slash home directory and send it to the slash dev tape device so let's say there is a tape device attached to your linux operating system and you want to send the home home directory you you want to tar the file or you want to tape of the archive file and send it to slash dev slash tape device so what do you use so you have to basically tar the file so if you don't understand what tar is star is basically like zipping your file in a windows operating system so now you use a hyphen xpf option is used to extract files from an archive i can cvf file is basically to turn it together xvf is to or unturret it basically removes the tar okay now uh cvf slash dev slash tape slash home so what happens is this is the destination and this is the directory which will be tarred together and that file will be sent into this destination directory so this is the command you use for that so not just home directory any directory or any file you want to turn send it to a particular location or a particular device this is the command you use 13th question suppose your ftp server is hacked and the entire server needs to be restored how would you restore the original kernel system files so now the ftp server which you have is hacked and the entire server needs to be restored so what can be done we cannot restore the entire operating system from the tape backup device therefore we should reinstall the core operating system that is you cannot directly reinstall the operating system just from the tape device which you have just from the backup device which you have but instead you'll have to reinstall the operating system and once it is re installed then you will have to basically restore the system configuration uh basically the users the details of the system everything should be restored and also the user data and all the other files from the backup device then can be moved to the linux system which you have just installed so that's how it works and yeah so that's basically it you cannot directly take all the details and put it into the system first you have to reinstall the core operating system and once it is installed you'll have to take the configuration files and user data and all the other files into the system which you just installed the 14th question why should you avoid telnet to administer a linux system remotely so telnet uses the most insecure method of communication so basically that's the reason why you shouldn't use telnet because it's pretty insecure it basically sends data across the network in a text format that anybody can read so if you get into the network you can basically take this file and check out this so check out the data within the file because it's not encrypted and in that case it's just plain text and anybody who finds out the password which is being sent using just a simple networking tool now it includes the passing of the login credentials in plain text anyone running a sniffer on the network that is let's say you have an intra network let's say it's a college network in that case most of the time people don't care about using a more secure line of communication they just go with telnet because it's pretty easy to set up in that case it sends out plain text and if college student if anybody uses just a sniffer they can get those files and they can basically start uh using whatever network the college is using so make sure you don't use telnet so you can see in a few seconds by each dropping on a telnet login session you can get the control of the device which is being which is sending that information so now the 15th question name four configuration tools configuration management tools used in unix unix-like operating systems so there are mainly for jeff ansible puppet and cf engine so i know about chef puppet and a little bit about ansible so now chef and puppet basically are configured so all of these are configuration management tools they do the same tasks so the common task here is they are like a master to multiple clients or multiple linux servers whenever you want to upgrade or whenever you want to run a configuration file in hundreds of servers you can send it to chair for puppet or ansible or cf engine and they'll make sure it runs on all the servers which you have you don't need to open each and every server and run the configuration file you should set up chef which basically manages all the servers for you so i'm just taking chef as an example so these are the four configuration management tools coming to the sixteenth question what is the difference between cron and anachron so now if you know what is uh chron uh an anachron obviously you already know the answer so now let me explain what exactly is cron and anachron so minimum granularity with cron is in minutes when it is in days with anachron so first let me tell you what is crown and anachron so basically cron or anakrun both are used to schedule tasks in the future so you can schedule a particular task let's say you want to take a backup of file you can schedule the task use you by creating a cron tab script file and that will automatically execute at that particular time which you have mentioned and it will be basically take a backup of that file so this is the this is the basic task of cron and anachron so now you can use cron to run in minutes that basically means you can set two minutes you can set a crown tab for minutes but using anachron you can only set it in days that is it can only repeat running or it can only work with days but chron can work in minutes cron jab can be scheduled uh by any normal user so even i can do even you can do if you're using a linux server and i'm just a normal user and there is also super user there is also administrator so any of them can create a cron job but anachron can only be created by a super user or the administrator kron expects the system to be up and running while anachron doesn't expect this all the time in case of vanaclone if a job is scheduled and the system is down at this time it'll still execute the job as soon as the system is up and running so in the case of cron it'll if the system is down basically it won't have any idea of what to do so basically the time passes and once the time passes the crown job will not run but the anacron job even though the system was down at the time if the time has gone beyond the set time it'll still run the job and execute it so now cron is ideal for servers anachron is ideal for both desktops and laptops so cron ideal for servers in the sense if you are running a task for your application which is hosted in the cloud server in that case go with cron if you're doing it for a local desktop or a laptop go with anachron crown should be used when we want a job to be executed at a particular hour and minute and anachron should be used when the job can be executed at any time basically means if the time passes anachron will still run and execute it but cron won't do if the time passes it won't do it'll only do at the exact minute or the exact heart you have mentioned so that's the only difference between cron and uh anachron in this case but uh so chron is suitable suited for servers anachronist suited for desktops and laptops i think you got the difference between chronolog they both are used to schedule tasks and crown can be only used by all kinds of users anachron can only be used by a super user or an admin so now which command is used to check check the number of files disk space and each user's defined quota so the rep quota command is used to check of a user's defined quota along with the disk space and the number of files used so over here you can see the command being used requota minus a so this report is for this particular device so block race time seven days so you can see all the tasks which are done all of the users who are using it and how much data they have used over here you can see the used data so you basically set up file limits you can basically set up all kinds of limits over here and to check the each co each user's quota each user's limit you should use the rep quota minus a command to see all of that this command gives a summary of the user's quota that is how much space and files are left for the particular user each user has a defined quota in linux this is done mainly for security assist as it restricts files from unwanted access dakota can be given to a single user or to a group of users so i think you got the answer for this question so they asked what is the command to check the number of files or disk space which is basically alerted for a particular user so to check out that you'll have to use rep quota minus a or space hyphen a the next question is what is the name and path of the main system lock by default the main system log is available in slash var log slash messages this file contains all messages and scripts written by the user by default all scripts are saved in this file this is the stand-up sys standard system log file which contains messages from all the system software as well non-kernel boot issues and messages that go to d message the d message file is a system file that is written upon the system boot so the name of the main system log is messages and the path is slash var slash log slash messages so the user scripts the uh scripts or messages from system software non-kernel boot issues or any kinds of messages will be sent to this particular location in default the 19th question can we convert a linux computer into a router in order to enable multiple machines to work on the same internet connection if yes how we can convert a linux pc into a router so that it can act as an ip gateway for a network this process of turning a linux mission to a router is referred to ip masquerade so you'll have to do linux ip masquerading to enable this and the other internal computers that are linked to the linux system to get connected to the internet in linux we can perform ip masquerading by following the below steps so now in the next slide i have all the steps so to understand this basically you there is a router which has uh basically limited connection so let's say 20 connections and there are 20 more systems so now we want to give internet connection to those servers or to those computers in that case you can basically change the linux computer into a router so to do that you'll have to do ip mass grading and to do that these are the steps so first you have to make sure that the linux pc is having an internet connection so whichever pc you're going to change it into a router should have internet connection and also it should have a lan connection which connects across to all of the other computers in fact a linux pc will be having a ppp connection and an ethernet card so obviously an ethernet card will be connected to it so now as the default gateway for tcp ip networking all the other systems on our lan use the linux mission so apart from the default gateway every other system uses the expression hence we have to use the same dns addresses provided by the internet service provider on our all systems so that basically means on the gateway the main ip address to use the internet so that particular dns addresses should be provided sorry i have to use the exact same dns address in all of the computers even though they're connected to this particular linux system so now for enabling ip forwarding we'll have to use the following command so first you'll have to echo one greater than uh greater than it basically writes that information into this particular variable okay so now slash proc slash sys slash net slash ipv4 and inside that high p underscore forward so we are basically forwarding the ip addresses to all the other computers so for checking whether we have ip forwarding enabled already we can use the following so basically this is to enable ip forwarding but if it's not working that basically means ip forwarding is already enabled so to check that use this command uh systemctl net.ipv4.i underscore forward so when you check this if it shows zero that basically means it's not enabled so or you can just use cat for the this particular command so basically what we are doing is we are basically toggling it from zero to one so once we toggle it from zero to one you start forwarding the ip address to other computers so to check we have these two steps and once all of that is done finally we will run the ip tables for setting up those rules that enable ipmax grading so inside iep tables you can set up what are the ip addresses that can be used by the linux computer and the other client computers so i think this is it you just have to toggle uh ip forwarding once you toggle ip forwarding iptables is like a firewall in which you set up uh like whether those linux systems can use these domains from the internet so that's it once you set it up all the links systems which are connected to this particular computer which is turned into a router right now will get internet access the 20th question and the last question in the intermediate questions so in linux how would how could you or how would you ma change the window manager the slash dot x i n i t r c file or synetric file lets us change the window manager that we will use while logging into the x window session so the dot in the file so it basically tells a particular file is a hidden file it also means that this file will not be present when we carry out a normal directory listing and in order to set up a window manager you'll have to execute the following command so to change before changing it you'll have to set up a window manager to set up a window manager you'll have to use exec window manager command once we are done with this part the next step is to save the file this way a new window manager opens up every time we run a start x and it becomes the default now let's check out the commands used for starting some very common desktop environments and windows managers so if you have used linux systems you would know about window maker or gnome or blackbox because these are popular window managers mostly i use gnome so basically to start off these window managers you will have to use these commands so for gnome you'll have to use gnome hyphen session and for black boxes black box in lower case start kde wmaker fvwm iswm so basically to run all these window managers you'll have to just use it that's it so you don't have to do anything else you'll have to install these window managers already into your system and then just run these commands and it would change the window manager for you okay so we've seen the intermediate questions as well now let's look into the advanced interview questions start off with it how were shadow passwords given in linux so we already know about that we already know the basics there is there are two files password and shadow password has x shadow has the details so now in linux pw convey command is used for providing the shadow passwords so shadow passwords are given for better system security we already established that this command creates the shadow and changes all passwords to x in the password file so this is the command which does that particular action so we saw that the password file will contain the passwords as x and shadow file actually contains the actual information so that is done by the pw convey command first the entries in the shadowed file which don't exist in the main file are removed so the first line basically means so there will be multiple entries in the shadowed file if those particular entries do not exist in the main file they'll get removed in the shadowed file because there is no use for them then the shadowed entries that don't have x as the password in the main file are updated so in the main file all of those passwords are updated to x and also they are updated in the shadowed file any missing shadow entries are also added so if there are any missing shadow entries in the shadow file but it is available in the password file that will be added to the shadow file finally passwords in the main file are replaced with x these programs can be used for initial conversion as well to update the shadow file if the main file is edited by hand okay so this is how you do it it's pretty simple it's just the command pw convey you use but the steps are basically these if you use the command it will do all the things for you basically you remove all the entries in the main file if they do not exist in shadowed file and if they don't have the if they are not changed to x it will be updated in the main file and if there are any shadow entries which are missing in the shadow file which are available in the main file they'll get updated and also added that's it coming to the next question what daemon is used for scheduling commands so we already established what cronus so cron exactly is used over here it is called cron tab over here daemon which you use for scheduling commands is cron tab command so crontab command is used to scheduling commands to run at a later time so crontab is a command which is basically used to set up commands to run later over here you can see crontab hyphen user username and file so inside this file you will have all the commands which you need to run at that particular time and over here hyphen l displays the current crown tab entries so this is the way you write this the normal syntax so inside this file you have all the commands which will run once the time arrives so this hyphen r removes the current contract so let's say you have created a cron tab and you want to remove it in that case you'll have to use minus r and minus e basically it opens the visual editor and once it opens the visual editor you will be able to edit the things inside of it when a user exists from the editor the modified crown tab will be installed automatically each user can have their own contact and though these are files in slashware they are not intended to be edited directly so basically there are files but you shouldn't edit them directly you should use the minus e command to edit them using the visual editor provided by the crown tab itself so the daemon used for scheduling commands is crontab coming to the 23rd question so what shell does a linux administrator assign to a pop3 mail only account okay so now a linux administrator assigns a pop3 mail only account to a bin slash false shell so it basically means the it's a fake shell okay so now however assigning a bash sell to a pop3 mail only account gives the user the login access which is usually avoided so the bin slash no login shell can also be added so the pop3 mailing account mail only account is added to two different shells false and no login this shell is provided to the user when we don't want to give shell access to the user it is mainly meant for the security of the shells so you give this particular cell usage because you don't want the user to get into your shell now pop3 is basically used for downloading mail to mail programs so you basically download the mails online and you can read it anytime offline so now this account is assigned to slash bin false shell or slash bin no login shell both shells are the same as they do the same work of rejecting the user to the shell so basically if somebody is trying to illegally uh download emails in that case if you have provided them the access to false or no login so basically they won't be able to enter the shell itself they'll be rejected before logging in the main difference between these two shells between false and no login shell is that uh the file shell basically shows the incorrect code and any usual coding when a user logs in into it whereas the no login shell simply tells us that no such account is available therefore the no login shell is used often in linux so basically the difference is the false account or the false shell shows incorrect coding which does not allow the user to get into the shell but the no login shell basically tells the user that there is no shell like this available you cannot log into this that's it so this is the linux shell which is basically assigned to a pop3 mail only account faults are no login shells coming to the 24th question if a volume group named vg0 already exists and we need to extend this volume group up to 4 gb how do you do it so there is a volume called vg0 you'll have to extend it to 4gb so to do this you need a command so first you need to create a physical volume slash dev sda7 or a name which you like sda7 or whichever name you want to provide of size 4gb so once you've created a physical volume of size 4gb then you will run the command vg extend the name of the volume group which in this case is vg0 and once that is provided you'll have to provide the device name which you have created which is the size of 4gb so now the already existing volume group will add this 4gb to that group and 4gb will now be added and this is how you do it coming to the 25th question is there any relation between the mod probe dot configuration file and network devices yes this file assigns a kernel module to each network device so any network device which is connected so the modprobe.configuration file basically assigns a kernel module to each of these network devices so they can be running their own tasks over the kernel modules over here alias ethernet 0 b44 here b44 is the kernel module for network device ethernet 0. we can confirm whether this module b44 is present or not by following command so ls mod grep b44 so the b44 kernel module exists and it exists because of the modbroker configuration file mod probedup configuration file is the one which assigns a kernel module to the network devices so one of the network device is an ethernet device basically connecting the internet right so it's an ethernet 0 device and basically it has a kernel module b44 assigned by the modprobe dot configuration file coming to the 26th question it's simply what is yum so yum is the package manager so it stands for yellow dog updater so right now it's hello dog updater modified so it's called yum because it's based on the yellow dog updater but it is a little varied it's modified that's it like how vi changed to them the text editor like that uh you you or why you changed to yum so yellow dog is a version of linux for the power architecture hardware and is rpm based just like red hat enterprise and fedora so it's basically a version of linux which lets you gather files or gather packages from multiple locations so now yup that is yellow dock updater and later yum right now we use yum which is ella dog updater modified was written by the linux community as the way to maintain an rpm based system so rpm is an open source package manager from where you can download all the open source libraries and packages which you need for your linux system so to download that you will have to use the yellow dog updater or the yellow dog updater modified which is yum that's it it's written by the linux community to keep it open source and download all the open source libraries and files and applications directly from the rpm package manager coming to the 27th question what's the role of kudzu kudzu is used to detect new hardware so the red hat linux runs a hardware discoverer called kudzu so now when attempting to identify a serial port kudzu resets the serial port this stops the serial console kudzu is configured from the following file so atc syst config slash kudzu kuju can be prevented from resetting hardware by setting the configuration parameter safe to yes so basically it tries to identify new software and it tries to reset it but to stop it from resetting you'll have to just set the parameter safe to yes and then it just identifies the incoming hardware and it won't change anything it won't configure anything that's it uh the 28th question is the difference between ext2 and ext3 file systems so now ext3 file system is an enhanced version of ext2 file system so ext2 is the older version the most important difference is that ext2 and axt3 is that ext3 supports journaling so that basically means exe2 doesn't after an unexpected power failure or system crash also called an unclean system shutdown each ext file system must be checked for consistency by the e2 fsc program this is a time consuming process and during this time any data on the volumes is unreachable so basically if there is a fire uh if there is a power failure or if there is a system crash which causes the servers to go down if you're using an ext2 file system in that case you'll have to check each and every ex2 file system ext257 which is connected to the server by the e2fsck program so that basically means in that case you'll have to run the e2fsck program in each and every ext2 file system and that is time consuming so now ext3 has journaling so that basically means by providing ext3 file system means that this sort of file system check is no longer needed after an unclean system shutdown it basically keeps all the files safe you don't need to run e2fsck each and every time after an unclean shutdown that is a shutdown when the system goes down suddenly without saving anything or doing anything so ext3 does not get affected in this case now finally the 29th question explain the slash proc file system so the slash proc file system is a virtual file system that provides detailed information about the linux kernel hardware and processes running within it the files under this proc directory are named virtual files since slash proc contains virtual files it is called a virtual file system so basically all the virtual files are available in the proc directory therefore it's called a virtual file system these virtual files have unique qualities most of them are listed as zero bytes in size virtual files such as interrupts memory info mounts and partitions provide an up to the moment glimpse of the system's hardware so basically it's a really important directory it is called the virtual file system so basically if there are any interrupts the about the memory info that is the free memory available memory the disks which are mounted are the partitions which are available in the pc so all of that information is in the virtual files which are stored in the virtual file system which are basically noted as zero bytes because they are very very small or very short files so these provide an up to the moment glimpse of the systems hardware that basically means you can check out the real-time information of the system's hardware using the proc file system or the virtual file system so you can see the virtual file system is over here and all the processes run and all the processes which are running will go through it and the virtual file system will know all the processes which are running at that particular time and the final question how do you create an ext4 file system so right now ext4 is the most commonly used file system not ext3 not ext2 so we can create an x24 file system with this command so mke to fs so it does basically make file system so you can use mke to fs minus t basically denotes which file system you want to create in this case it is exe4 and slash dev and the slash device name or the folder name in which you'll have to create the ext4 file system so this is the command which you'll have to use which is make two file system hyphen t your file system name which is ext4 and then the device name and that's it you have created an ext4 file system successfully okay guys i think we've completed all the 30 questions thank you

Channel: Intellipaat

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Keywords: Linux Interview Questions And Answers, Linux Admin Interview Questions, linux interview questions and answers for experienced, linux interview questions and answers for freshers, linux interview questions, linux tutorial for beginners, linux administration tutorial, linux training, linux administration training videos, linux admin interview videos, intellipaat linux interview questions and answers, linux, linux operating system, linux tutorial, linux commands

Id: oT-n576S0VQ

Length: 50min 19sec (3019 seconds)

Published: Sun Dec 13 2020