• Ubuntu
• Centos
• Fedora
• Debian
• OpenSuse
• ArchLinux
• Slackware

• BIOS
• MBR
• GRUB
• Kernel
• Init
• Runlevel

• https://en.wikipedia.org/wiki/Sticky_bit
• https://www.geeksforgeeks.org/setuid-setgid-and-sticky-bits-in-linux-file-permissions/

• https://serverfault.com/questions/138427/what-does-virtual-memory-size-in-top-mean
• https://elinux.org/images/4/4c/Ott.pdf

• https://en.wikipedia.org/wiki/Zombie_process
• https://www.geeksforgeeks.org/zombie-processes-prevention/
• https://stackoverflow.com/questions/16944886/how-to-kill-zombie-process

• In most cases you will get unbootable system
• https://askubuntu.com/questions/962660/what-happens-if-you-delete-the-root-user

• https://dev.to/rrampage/surviving-the-linux-oom-killer-2ki9
• https://www.percona.com/blog/2019/08/02/out-of-memory-killer-or-savior/

• https://www.linuxjournal.com/content/oops-debugging-kernel-panics-0
• http://www.linuxandubuntu.com/home/things-to-know-about-linux-kernel-panic

• https://www.geeksforgeeks.org/network-address-translation-nat/
• https://www.comptia.org/content/guides/what-is-network-address-translation

• Application layer: Check if servers are correctly configured and services up and running
• Transport layer: Check ports, check ping from server to server
• Network layer: Check firewall and networking setting. Also check routes, dns and ARP tables.

• nmap - if you need check all ports for remote server
• netstat - for localhost

#!/bin/bash

VAR1="string1"
VAR2="string333"

if [ "$VAR1" = "$VAR2" ]; then
  echo "Strings are equal."
else
  echo "Strings are not equal."
fi

#!/bin/bash
array=("A" "B" "C" "X" )
echo ${array[0]}

#!/bin/bash
for i in {1..10}; do
    echo $i
done

• https://realpython.com/
• https://python-for-system-administrators.readthedocs.io/en/latest/

• https://realpython.com/python-pep8/

• https://www.youtube.com/watch?v=ZS_kXvOeQ5Y
• https://www.geeksforgeeks.org/difference-between-sql-and-nosql/

• https://intellipaat.com/blog/tutorial/sql-tutorial/tables-in-sql/

• https://www.geeksforgeeks.org/data-replication-in-dbms/

• https://www.dynamodbguide.com/what-is-dynamo-db/

• https://git-scm.com/book/en/v2/Getting-Started-What-is-Git
• https://git-scm.com/book/en/v2/Getting-Started-What-is-Git

• Documentation
• Markdown
• Fully Distributed
• Simplicity
• Branching model
• open source

• https://guide.freecodecamp.org/miscellaneous/git-pull-vs-git-fetch/

• https://stackoverflow.com/questions/8358035/whats-the-difference-between-git-revert-checkout-and-reset

• https://www.atlassian.com/git/tutorials/rewriting-history/git-rebase

• git reset --hard HEAD~1 - not a true way cuz you will lost all changes
• git revert <commit-id> - good way

• https://medium.com/@patrickporto/4-branching-workflows-for-git-30d0aaee7bf
• https://www.atlassian.com/git/tutorials/comparing-workflows/gitflow-workflow

• https://linuxcontainers.org/lxc/introduction/

• https://opensource.com/resources/what-docker

• https://dzone.com/articles/top-10-benefits-of-using-docker

• https://goinbigdata.com/docker-run-vs-cmd-vs-entrypoint/

• https://docs.docker.com/storage/volumes/

• https://success.docker.com/article/introduction-to-user-namespaces-in-docker-engine

• https://www.padok.fr/en/blog/container-docker-oci

• https://dev.to/brpaz/using-docker-multi-stage-builds-during-development-35bc

• https://opensource.com/life/16/9/containing-container-chaos-kubernetes

• https://kubernetes.io/docs/concepts/overview/what-is-kubernetes/
• Kubernetes in 5 minutes https://www.youtube.com/watch?v=PH-2FfFD2PU

• https://kubernetes.io/docs/concepts/workloads/pods/pod/

• https://kubernetes.io/docs/reference/kubectl/overview/

• https://www.dasblinkenlichten.com/understanding-cni-container-networking-interface/

• https://dev.to/kaoskater08/building-a-headless-service-in-kubernetes-3bk8

• CPU is in milicores and memory in bytes
• https://www.noqcks.io/notes/2018/02/03/understanding-kubernetes-resources/

• https://cloud.google.com/kubernetes-engine/docs/how-to/stateful-apps
• https://kubernetes.io/docs/tasks/run-application/run-replicated-stateful-application/

• Ansible for Devops https://leanpub.com/ansible-for-devops
• https://serversforhackers.com/c/an-ansible-tutorial
• https://medium.com/quick-code/top-tutorials-to-learn-ansible-33afd23ea160

• https://docs.saltstack.com/en/master/topics/tutorials/walkthrough.html
• https://www.digitalocean.com/community/tutorials/an-introduction-to-saltstack-terminology-and-concepts

• https://www.guru99.com/puppet-tutorial.html

• https://www.youtube.com/watch?v=_zCyLT33moA
• https://www.atlassian.com/continuous-delivery/continuous-integration

• https://www.atlassian.com/continuous-delivery/principles/continuous-integration-vs-delivery-vs-deployment
• https://aws.amazon.com/devops/continuous-delivery/

• https://www.atlassian.com/continuous-delivery/continuous-deployment

• https://www.katalon.com/resources-center/blog/benefits-continuous-integration-delivery/

• https://www.udemy.com/share/101WuI/
• https://www.youtube.com/playlist?list=PL9ooVrP1hQOGM6eCsjnfAousUSvpqD8dW&ref=hackr.io
• https://jenkins.io/doc/book/

• Tekton https://github.com/tektoncd
• ArgoCD https://argoproj.github.io/argo-cd/
• JenkinsX https://jenkins-x.io/

• https://www.youtube.com/watch?v=TFLQcgZr0no
• https://www.udemy.com/share/101ZdI/
• https://itnext.io/terraform-tutorial-part-1-intro-and-basic-concepts-7a27ae7722b6

• https://www.freecodecamp.org/news/terraform-modules-explained/

* Terraform init command is used to initialize the working directory containing Terraform configuration files.
* It is used for Plugin Installation.
* It is also used for Child Module Installation.
* It is used for Backend Initialization.
* You can safely run this command multiple times.

• https://www.ibm.com/cloud/learn/iaas-paas-saas

• https://azure.microsoft.com/en-us/overview/what-are-private-public-hybrid-clouds/

• https://azure.microsoft.com/en-us/overview/what-is-a-public-cloud/
• examples: AWS, GCP, DegitalOcean, Azure

• https://searchitchannel.techtarget.com/definition/cloud-services

• https://en.wikipedia.org/wiki/Serverless_computing

• https://medium.com/javarevisited/5-best-aws-courses-for-beginners-and-experienced-developers-to-learn-in-2021-563212409fbd
• https://docs.aws.amazon.com/

• https://www.udemy.com/topic/google-cloud/
• https://linuxacademy.com/course/google-cloud-data-engineer/