This is perfect. If you can send more task like this (for beginners) and more complex tasks, I would be very thankful. In this way I can try things and learn something new, because I had no idea that something like SHA256 exists

There are some good resources named in the other posts too, especially the Shotts book. The whole book is good but section four is especially important.

Here are a few more for the interactive shell:

configure sudoers to run a script as another, but non-root, account
run a script as another non-root account using sudo
configure doas to allow starting, stopping, restarting, and reloading a service
start, stop, restart a service using doas
edit a service's configuration
reload that service using doas
fetch an ISO image using wget
verify the integrity of the ISO using sha512sum
verify the authenticity of the ISO using sq or gpg
list nftables rules
add a (temporary) rule to nftables
add a (permanent) rule to nftables
start a tmux session
detach the tmux session
reattach the same tmux session
make an new window in tmux
view a log file with a pager
track the log file as it grows using tail
pipe tail into grep or awk to select only specific log entries
switch windows in tmux
check the local date and the UTC date
check a remote service with netcat
use openssl to view the valid period of an x509 certificate
use SSH keys to log into a remote host (-i)
set up a while loop to re-log into the remote host automatically on an intermittent network
use zenity to pop up a notice at a specific time or upon script completion (hint DISPLAY=:0.0)
find out which accounts are logged in and active with w
find process ids with a certain name using pgrep (-d)
find details for said process ids using ps (-p, -o)

YMMV.

Some of those are common tasks in general others might be common for some people in some activities but not others. Be sure to at least skim the manual pages for each utility. It'll be very useful to be comfortable doing that and learning how to look up the details easily when you need them. So it is more important to learn to find and skim manual pages than to try to remember any specific utilities. That'll come automatically with repetition anyway. Though if you are interested in servers, I would recommend finding your way around tmux, ssh, sudo or doas, and some basic shell scripting.

Again, see posts #6 and #10 among the others above.

There are a bunch of good beginner tutorials in youtube. Look for the complete courses that follow some sort of line, otherwise you can get lost learning a gazillion different things here and there. Here are a few good starting points for begginers, follow their playlists:

Linux sysadmin basics
https://www.youtube.com/watch?v=bju_...PmiRarU7hrpnwK

CentOS tutorial (98% of this one applies to any linux distribution)
https://www.youtube.com/watch?v=Mi6G...mi5FmBGIZ8cNJE

Take it easy and have fun, everything starts clicking and making sense after some time, then it gets REALLY fun and productive.

http://minimal.idzona.com/the_dao_of...linux_live.txt

(I use MLL [a M$Win VM] to $0 phone-tutor beginners on kernel & core CLI)


IF I were to buy just one book: https://www.amazon.com/Linux-Adminis.../dp/1260441709
would probably beat out the best one: How Linux Works & various Linux Bibles

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Thank you everyone. Community on this forum is very helpful.
I didn't expect so many replies. Every reply is important for me and
reach me something new. Have a nice day everyone

1 members found this post helpful.