Piotr Kowalski bitroniq

OpenSSL 🔐

Install

Install the OpenSSL on Debian based systems

sudo apt-get install openssl

Generate private key

openssl genrsa -out privatekey.pem 1024
Generating RSA private key, 1024 bit long modulus (2 primes)
......................+++++
....................+++++
e is 65537 (0x010001)

JQ to filter JSON by value

Syntax: cat <filename> | jq -c '.[] | select( .<key> | contains("<value>"))'

Example: To get json record having _id equal 611

cat my.json | jq -c '.[] | select( ._id | contains(611))'

Remember: if JSON value has no double quotes (eg. for numeric) to do not supply in filter i.e. in contains(611)

log-shipping-api

Snippets for interview

A collapsible section containing markdown

Click to expand!

Heading

A numbered
list
- With some

Sub bullets

Looking to create a Software RAID 1 setup for your 2-disk server on Ubuntu Server 20.04?

Let's start with the basics: the official guide by Ubuntu (https://ubuntu.com/server/docs/install/storage) is outdated/wrong. And as of March 2021 it's possible that there's a bug as well with how the bios_grub partitions are created when using multiple disks.

Now on to the solution:

Select "Custom storage layout" when you reach the storage configuration step of the installer.
If the disks have existing partitions, click on each disk under AVAILABLE DEVICES and then select REFORMAT. This will (temporarily) wipe out the partitions.

OpenVPN connect on boot aka SBL start-before-logon

Official solutions from OpenVPN

Using nssm.exe

OpenVPN/openvpn-gui#77 (comment)

Tcpdump

Tcpdump is a commandline tool that is used to dump traffic on a network. This tool comes in hand when you want to analyse network captures within the command line. Basically it can do most of the wireshark job.

NOTE This guide might not be complete it just serve as a reference to me.

Additional Note & Reference

	#!/bin/bash

	################################################################################
	#
	# Helper variables to print text using some colors.
	#
	################################################################################

	# Restore to default colours
	RESTORE='\033[0m'

	#!/bin/bash
	while true; do speedtest-cli --csv; sleep 300; done
	## Example
	## 47590,Telewizja Kablowa SMNT,Nowy Tomyśl,2022-06-28T14:39:25.018280Z,147.92933777800633,18.491,214250762.91277993,182789875.8979877,,185.49.31.123
	## speedtest-cli --csv --csv-header
	## Server ID,Sponsor,Server Name,Timestamp,Distance,Ping,Download,Upload,Share,IP Address

	while true; do speedtest-cli --simple \| tr '\n' ' ' \| ts ; echo "" ; done
	# Jun 28 16:47:33 Ping: 18.361 ms Download: 255.12 Mbit/s Upload: 190.35 Mbit/s
	# Jun 28 16:47:52 Ping: 20.787 ms Download: 250.77 Mbit/s Upload: 172.12 Mbit/s