Mithun Technologies +91-9980923226 devopstrainingblr@gmail.com
http://mithuntechnologies.com/
http://mithuntechnologies.co.in/How to check
Memory stats and CPU stats as a Linux admin?
Ans)
How to reduce
or shrink the size of LVM partition?
Ans)
How can you
enhance the security of password file?
Ans)
What is the
difference between Cron and Anacron?
Ans)
What command
is used to check the number of files, disk space and each user’s defined quota?
Ans)
How can you
manage memory in linux machines?
Ans)
What is the
name and path of the main system log?
Ans)
How to manage
logical volumes?
Ans)
Explain /proc
filesystem?
Ans)
What are the
fields in the/etc/passwd file?
Ans)
Subscribe our YouTube channel for more Free DevOps videos.
https://www.youtube.com/channel/UC-Jr307MbEREy8bG6McwD6w
How do you terminate
an ongoing process?
Ans)
How can you
know the execution time of a command?
Ans)
How can you
append one file to another in Linux?
Ans)
How you can
run a Linux program in the background simultaneously when you start your Linux
Server?
Ans)
Difference in
soft link and hard link?
Ans)
How to find a
particular word from a file?
Ans)
What is stop
command?
Ans)
How to stop
particular process using Linux command?
Ans)
Can we delete
content in a file by using SED command? How to do?
Ans)
How to rename
the name of a file or a directory?
Ans)
Using mv command
What is
stored in each of the following paths?
/bin, /sbin, /usr/bin and /usr/sbin
/etc
/home
/var
/tmp
Ans)
What is
special about /tmp directory when compared to other directories?
Ans)
Explain each
field in the output of `ls -l` command
Ans)
It shows a
detailed list of files in a long format. From the left:
file
permissions, number of links, owner name, owner group, file size, timestamp of
last modification and directory/file name
What are
hidden files/directories? How to list them?
Ans)
Explain
piping. How do you perform piping?
Ans)
Running the
command df you get "command not found". What could be wrong and how
to fix it?
Ans)
Subscribe our YouTube channel for more Free DevOps videos.
https://www.youtube.com/channel/UC-Jr307MbEREy8bG6McwD6w
How do you
schedule tasks periodically?
Ans)
How to check
which commands you executed in the past?
Ans)
How to change
the permissions of a file?
Ans)
What does the
following permissions mean?:
777
644
750
Ans)
What this
command does? chmod +x Bhaskar.txt
Ans)
Explain what
is setgid and setuid?
Ans)
What is the
purpose of sticky bit?
Ans)
What the
following commands do?
chmod
chown
chgrp
Ans)
You try to
delete a file but it fails. Name at least three different reason as to why it
could happen
Ans)
What is
systemd?
Ans)
On a system
which uses systemd, how would you display the logs?
Ans)
Describe how
to make a certain process/app a service
Ans)
Where system
logs are located?
Ans)
How to follow
file's content as it being appended without opening the file every time?
Ans)
What are you
using for troubleshooting and debugging network issues?
Ans)
What are you
using for troubleshooting and debugging disk & file system issues?
Ans)
What are you
using for troubleshooting and debugging process issues?
Ans)
What are you
using for debugging CPU related issues?
Ans)
Explain
iostat output
Ans)
How to debug
binaries?
Ans)
What kind of
information one can find in /proc?
Ans)
Can you
create files in /proc?
Ans)
What is the
difference between CPU load and utilization?
Ans)
How you
measure time execution of a program?
Ans)
What is a
kernel, and what does it do?
Ans)
How do you
find out which Kernel version your system is using?
Ans)
What is a
Linux kernel module and how do you load a new module?
Ans)
Explain user
space vs. kernel space
Ans)
What are
system calls? What system calls are you familiar with?
Ans)
What
virtualization solutions are available for Linux?
Ans)
What is KVM?
Ans)
What is SSH?
How to check if a Linux server is running SSH?
Ans)
Why SSH is
considered better than telnet?
Ans)
What is
stored in ~/.ssh/known_hosts?
Ans)
You try to
ssh to a server and you get "Host key verification failed". What does
it mean?
Ans)
What is the
difference between SSH and SSL?
Ans)
What
ssh-keygen is used for?
Ans)
Subscribe our YouTube channel for more Free DevOps videos.
https://www.youtube.com/channel/UC-Jr307MbEREy8bG6McwD6w
What is SSH
port forwarding?
Ans)
What is
Globbing?
Ans)
What are
wildcards? Can you give an example of how to use them?
Ans)
Explain what
will ls [XYZ] match
Ans)
Explain what
will ls [^XYZ] match
Ans)
Explain what
will ls [0-5] match
Ans)
What each of
the following matches
?
*
Ans)
What do we
grep for in each of the following commands?:
grep
'[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}' some_file
grep -E "error|failure" some_file
grep '[0-9]$' some_file
Ans)
Which line
numbers will be printed when running `grep '\baaa\b'` on the following content:
aaa bbb
ccc.aaa aaaaaa
Ans)
What is the
difference single and double quotes?
Ans)
What is
escaping? What escape character is used for escaping?
Ans)
What is an
exit code? What exit codes are you familiar with?
Ans)
Tell me
everything you know about the Linux boot process
Ans)
What is
GRUB2?
Ans)
What is
Secure Boot?
Ans)
What can you
find in /boot?
Ans)
How to check
which disks are currently mounted?
Ans)
You run mount
command but you get no output. How would you check what mounts you have on your
system?
Ans)
What is the
difference between a soft link and hard link?
Ans)
True or
False? You can create an hard link for a directory
Ans)
True or
False? You can create a soft link between different filesystems
Ans)
What happens
when you delete the original file in case of soft link and hard link?
Ans)
Can you check
what type of filesystem is used in /home?
Ans)
What is a
swap partition? What is it used for?
Ans)
How to create
a * new empty file * a file with text (without using text editor) * a file with
given size
Ans)
You are
trying to create a new file but you get "File system is full". You
check with df for free space and you see you used only 20% of the space. What
could be the problem?
Ans)
How would you
check what is the size of a certain directory?
Ans)
What do you
know about LVM?
Ans)
Explain the
following in regards to LVM:
PV
VG
LV
Ans)
What is NFS?
What is it used for?
Ans)
What RAID is
used for? Can you explain the differences between RAID 0, 1, 5 and 10?
Ans)
Describe the
process of extending a filesystem disk space
Ans)
What is lazy
umount?
Ans)
What is
tmpfs?
Ans)
Idenfy the
wrong in below commands?
sed "s/1/2/g' /tmp/myFile
find . -iname *.yaml -exec sed -i
"s/1/2/g" {} ;
Ans)
What is
stored in each of the following logs?
Ans)
True or
False? both /tmp and /var/tmp cleared upon system boot
Ans)
How to check
what is the current load average?
Ans)
You know how
to see the load average, great. but what each part of it means? for example
1.43, 2.34, 2.78
Ans)
How to check
process usage?
Ans)
How to check
disk I/O?
Ans)
How to check
how much free memory a system has? How to check memory consumption by each
process?
Ans)
How to check
TCP stats?
Ans)
How to list
all the processes running in your system?
Ans)
How to run a
process in the background and why to do that in the first place?
Ans)
How can you
find how much memory a specific process consumes?
Ans)
What signal
is used by default when you run 'kill *process id*'?
Ans)
What signals
are you familiar with?
Ans)
What kill 0
does?
Ans)
What kill -0
does?
Ans)
What is a
trap?
Ans)
Every couple
of days, a certain process stops running. How can you look into why it's
happening?
Ans)
What happens
when you press ctrl + c?
Ans)
What is a
Daemon in Linux?
Ans)
What are the
possible states of a process in Linux?
Ans)
How do you
kill a process in D state?
Ans)
What is a
zombie process?
Ans)
How to get
rid of zombie processes?
Ans)
How to find
all the
Processes executed/owned by a certain user
Process which are Java processes
Zombie Processes
Ans)
What is the
init process?
Ans)
How to change
the priority of a process? Why would you want to do that?
Ans)
Can you
explain how network process/connection is established and how it's terminated?
Ans)
What strace
does? What about ltrace?
Ans)
Find all the
files which end with '.yml' and replace the number 1 in 2 in each file
Ans)
You run ls
and you get "/lib/ld-linux-armhf.so.3 no such file or directory".
What is the problem?
Ans)
How would you
split a 50 lines file into 2 files of 25 lines each?
Ans)
What is a
file descriptor? What file descriptors are you familiar with?
Ans)
What is NTP?
What is it used for?
Ans)
Explain
Kernel OOM
Ans)
Linux
Security
Ans)
What is
chroot? In what scenarios would you consider using it?
Ans)
What is
SELiunx?
Ans)
What is
Kerberos?
Ans)
What is
nftables?
Ans)
What
firewalld daemon is responsible for?
Ans)
Do you have
experience with hardening servers? Can you describe the process?
Ans)
Linux
Networking
Ans)
How to list
all the interfaces?
Ans)
What is the
loopback (lo) interface?
Ans)
What the
following commands are used for?
ip addr
ip route
ip link
ping
netstat
traceroute
Ans)
What is a
network namespace? What is it used for?
Ans)
How to check
if a certain port is being used?
Ans)
How can you
turn your Linux server into a router?
Ans)
What is a
virtual IP? In what situation would you use it?
Ans)
True or
False? The MAC address of an interface is assigned/set by the OS
Ans)
Can you have
more than one default gateway in a given system?
Ans)
Which port is
used in each of the following protocols?:
SSH
SMTP
HTTP
DNS
HTTPS
Ans)
What is
telnet and why is it a bad idea to use it in production? (or at all)
Ans)
What is the
routing table? How do you view it?
Ans)
How can you
send an HTTP request from your shell?
Ans)
What are
packet sniffers? Have you used one in the past? If yes, which packet sniffers
have you used and for what purpose?
Ans)
How to list
active connections?
Ans)
How to
trigger neighbor discovery in IPv6?
Ans)
What is
network interface bonding and do you know how it's performed in Linux?
Ans)
What network
bonding modes are there?
Ans)
What is a
bridge? How it's added in Linux OS?
Ans)
How to check
what is the hostname of the system?
Ans)
What the file
/etc/resolv.conf is used for? What does it include?
Ans)
What commands
are you using for performing DNS queries (or troubleshoot DNS related issues)?
Ans)
Do you have
experience with packaging? (as in building packages) Can you explain how does
it works?
Ans)
How packages
installation/removal is performed on the distribution you are using?
Ans)
RPM: explain
the spec format (what it should and can include)
Ans)
How do you
list the content of a package without actually installing it?
Ans)
How to know
to which package a file on the system belongs to? Is it a problem if it doesn't
belongs to any package?
Ans)
Where
repositories are stored? (based on the distribution you are using)
Ans)
What is an
archive? How do you create one in Linux?
Ans)
How to
extract the content of an archive?
Ans)
Why do we
need package managers? Why not simply creating archives and publish them?
How to look
for a package that provides the command /usr/bin/git? (the package isn't
necessarily installed)
Ans)
Linux
Applications and Services
Ans)
What can you
find in /etc/services?
Ans)
How to make
sure a Service starts automatically after a reboot or crash?
Ans)
You run ssh
127.0.0.1 but it fails with "connection refused". What could be the
problem?
Ans)
How to print
the shared libraries required by a certain program? What is it useful for?
Ans)
What is CUPS?
Ans)
What types of
web servers are you familiar with?
Ans)
What is a
"superuser" (or root user)? How is it different from regular users?
Ans)
How do you
create users? Where user information is stored?
Ans)
Which file
stores information about groups?
Ans)
How do you
change/set the password of a user?
Ans)
Which file
stores users passwords? Is it visible for everyone?
Ans)
Do you know
how to create a new user without using adduser/useradd command?
Ans)
What
information is stored in /etc/passwd? explain each field
Ans)
How to add a
new user to the system without providing him the ability to log-in into the
system?
Ans)
How to switch
to another user? How to switch to the root user?
Ans)
What is the
UID the root user? What about a regular user?
Ans)
What can you
do if you lost/forogt the root password?
Ans)
What is sudo?
How do you set it up?
Ans)
What is
/etc/skel?
Ans)
How to see a
list of who logged-in to the system?
Ans)
Explain what
each of the following commands does:
useradd
usermod
whoami
id
Ans)
Where can you
find information on the processor?
Ans)
How can you
print information on the BIOS, motherboard, processor and RAM?
Ans)
How can you
print all the information on connected block devices in your system?
Ans)
Give 5
commands which are two letters long
Ans)
What ways are
there for creating a new empty file?
Ans)
How `cd -`
works? How does it knows the previous location?
Ans)
List three
ways to print all the files in the current directory
Ans)
How to count
the number of lines in a file? What about words?
Ans)
You define
x=2 in /etc/bashrc and x=6 ~/.bashrc you then login to the system. What would
be the value of x?
Ans)
What is the
difference between man and info?
Ans)
Explain
"environment variables". How do you list all environment variables?
Ans)
How to create
your own environment variables?
Ans)
What a double
dash (--) mean?
Ans)
What the awk
command does? Have you used it? What for?
Ans)
How to print
the 4th column in a file?
Ans)
How to print
every line that is longer than 79 characters?
Ans)
What the lsof
command does? Have you used it? What for?
Ans)
What commands
you can use for searching files and/or directories?
Ans)
How can you
check what is the path of a certain command?
Ans)
Explain the
fork() system call
Ans)
Explain the
exec() system call
Ans)
What system
call is used for listing files?
Ans)
What system
call is used for creating a new process?
Ans)
What are the
differences between exec() and fork()?
Ans)
Why do we
need the wait system call?
Ans)
What execve()
does?
Ans)
What is the
return value of malloc?
Ans)
Explain the pipe()
system call. What does it used for?
Ans)
What happens
when you execute ls -l?
Ans)
What happens
when you execute ls -l *.log?
Ans)
What
readdir() system call does?
Ans)
What exactly
the command alias x=y does?
Ans)
Linux
Filesystem & Files
Ans)
How to create
a file of a certain size?
Ans)
Can you
describe how processes are being created?
Ans)
What does the
following block do?:
open("/my/file")
= 5
read(5,
"file content")
Ans)
Describe
three different ways to remove a file (or its content)
Ans)
What is the
difference between a process and a thread?
Ans)
What is
context switch?
Ans)
You found
there is a server with high CPU load but you didn't find a process with high
CPU. Ans)
How is that
possible?
Ans)
When you run
ip a you see there is a device called 'lo'. What is it and why do we need it?
Ans)
What the
traceroute command does? How does it works?
Ans)
What is
network bonding? What types are you familiar with?
Ans)
How to link
two separate network namespaces so you can ping an interface on one namespace
from the second one?
Ans)
What are
cgroups?
Ans)
Explain
Process Descriptor and Task Structure
Ans)
What are the
differences between threads and processes?
Ans)
Explain
Kernel Threads
Ans)
What happens
when socket system call is used?
Ans)
You executed
a script and while still running, it got accidentally removed. Is it possible
to restore the script while it's still running?
Ans)
What is the
difference between MemFree and MemAvailable in /proc/meminfo?
Ans)
What is
virtual memory?
Ans)
What is the difference
between paging and swapping?
Ans)
Explain what
is OOM killer
Ans)
What is a
Linux distribution?
Ans)
What Linux
distributions are you familiar with?
Ans)
What are the
components of a Linux distribution?
Ans)
Wildcards are
implemented on user or kernel space?
Ans)
If I plug a
new device into a Linux machine, where on the system, a new device entry/file
will be created?
Ans)
Why there are
different sections in man? What is the difference between the sections?
Ans)
Subscribe our YouTube channel for more Free DevOps videos.
https://www.youtube.com/channel/UC-Jr307MbEREy8bG6McwD6w
