linux interview questions

 Linux interview Questions from Tech Arkit:


1).There are three users in linux server A1,B1,c1.


1. provide access to A1 user ftp,telnet ans ssh commands


2.only ssh access to b1 user


3.only telnet access to c1 user


How will you provide access?


first we should edit the sudoers file


vi /etc/sudoers and vi sudo


A1 ALL = nopassword ;/bin/ftp,/bin/telnet,/bin/ssh


B1 ALL = nopassowrd :/bin/ssh


C1 ALL = nopassowrd :/bin/telnet



2).what is firewall?


its a security . which is used to filters and controls the traffic on a predefined set of rules.


firewall rule is defined as the blocks and protects the website .


3).what is selinux & selinux contexts?


system_u: selinux user

object_r : role

passwd_file: selinux type

so =sensivity level


ls -lZ command


How to check the selinux is enable on the file level?


we can execute the command like as the,


ls -lZ command 



so in this way we can check it out the selinux is enable on the particular file.


4).How do you check kernel version into linux os ?



we can execute the command like as the,


uname -a comamnd 


5).How will you install the packages in linux ?


install web server packages?



using yum and rpm packages to install the packages into linux os .



yum install httpd -y command 



so in this way we can install the webserver packages into linux os 


rpm -ivh 


i - instllations 

v-verbose

h-horse


where the package is located 



6).How will you check the memeory usage into linux os ?


we can execute the comamnd like as th,


top command


free -m comamnd


cat /proc/meminfo command


7).How will you reduce the LVM size, explain the procedure?


first unount the disk or filesystem


unmount /lv0


we can run the e2fsck to resolve any filesystem errors


e2fscak -f /dev/vg0/il


resize the filesystem 

resize2fs /dev/vgo/lv 40m


reduce the lvm size :


lvreduce -L 400m /dev/vg0/lv


next we need the mount the filesystem,


next we  need to edit the entries with the fstab filesystem

mount -a


check the filesystem using df -Th command:



8).How will you extend LVM size, explain the procedure>


before then we have to resize the filesystem in linux os:


resize2fs /dev/vg1/lv


lxextend _L +1G /dev/vg1/lv


9).How to check memeory,cpu , usage ,serial no,and model 

number?


cat /proc/meminfo

cat /proc/cpuinfo 


or else we have to execute the comamnd like as the


dmidecode 



10).explain linux boot process?


11).how to monitor cpu utilizations into linux os ?


12).






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