Dzhan85

#!/bin/bash
# Install docker
apt-get update
apt-get install -y cloud-utils apt-transport-https ca-certificates curl software-properties-common
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) \
   stable"
apt-get update

Dzhan85

Handling Multiple Github Accounts on MacOS

The only way I've succeeded so far is to employ SSH.

Assuming you are new to this like me, first I'd like to share with you that your Mac has a SSH config file in a .ssh directory. The config file is where you draw relations of your SSH keys to each GitHub (or Bitbucket) account, and all your SSH keys generated are saved into .ssh directory by default. You can navigate to it by running cd ~/.ssh within your terminal, open the config file with any editor, and it should look something like this:

Host *
 AddKeysToAgent yes

> UseKeyChain yes

Dzhan85

Problem

I have two Github accounts: oanhnn (personal) and superman (for work). I want to use both accounts on same computer (without typing password everytime, when doing git push or pull).

Solution

Use ssh keys and define host aliases in ssh config file (each alias for an account).

How to?

1. Generate ssh key pairs for accounts and add them to GitHub accounts.

Dzhan85

Questions are not from any actual exam!!!  



Q:  Create a job that calculates pi to 2000 decimal points using the container with the image named perl
and the following commands issued to the container:  ["perl",  "-Mbignum=bpi", "-wle", "print bpi(2000)"]
Once the job has completed, check the logs to and export the result to pi-result.txt.

Solution:

Dzhan85

Top Questions for Sysadmin Interview:

Disclaimer: These questions and answers aren't at all mine. These were scavanged around in the web. I hope it helps.

Basic:

1. What is Linux and also explain the basic components of Linux?

   Answer: Linux is the most commonly used operating system that is open source and free. For any computer, the operating system acts as the backbone, and it is most important software that is required for any computer.

Dzhan85

Some Jenkinsfile examples

Dzhan85

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

• -E: will describe the underlaying queries of the \ commands (cool for learning!)
• -l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

Dzhan85

echo "Обнуляем правила"
iptables -X
iptables -t nat -X
iptables -F
iptables -t nat -F

echo "Блокируем весь трафик"
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP

Dzhan85

#!/bin/bash
ip4="192.168.168"
ip6="fd00:168:168"
lan="eth0"
wan="eth1"

1_interfaces () {
cat << EOF > /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE="eth0"
NM_CONTROLLED="no"

Dzhan85

IPTables setup for a Linux-based Router

The following script will set the router's firewall to reject every thing coming from the WAN, while forwarding all the traffic from LAN to WAN.

#!/bin/sh

PATH=/usr/sbin:/sbin:/bin:/usr/bin

WAN=enp2s0