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let c1 = require('./currency-rates-2.json')

console.log('Date,', c1.from, 'to', c1.to)

let c1b = c1.batchList[0]
let ts = c1b.startTime
for (let i = 1; i < c1b.rates.length; i += 1) {
    let actualrate = c1b.rates[i] - c1b.rates[0]
    console.log(new Date(ts).toLocaleDateString() + ', ' + actualrate)
    ts += c1b.interval

nikolaybotev

// Brute force compound interest loan payment calculator

// Inputs
let amount = 100_000 // dollars
let interest = 10 // percent per year
let term = 30 // years

// Monthly Payment
let monthly_interest = (interest / 12) / 100
let no_of_payments = term * 12

nikolaybotev

#!/bin/bash

# pi-bootstrap
#
# Setup an Ubuntu Raspberry Pi image for headless boot.
#
# Copyright Nikolay Botev, MIT License
#

# Default settings

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(function () {
  function toCtDate(event) {
    const p2 = s => s.toString().length == 1 ? "0" + s : s;
    return `${p2(event.getUTCMonth()+1)}/${p2(event.getUTCDate())}/${event.getUTCFullYear()} ${p2(event.getUTCHours())}:${p2(event.getUTCMinutes())}:${p2(event.getUTCSeconds())}`;
  }

  const coinMap = {
    "Dogecoin": "DOGE",
    "Ethereum": "ETH"
  }

nikolaybotev

Screen Cheatsheet

Essentials

Technically all the commands in this section apply to screen sessions. For brevity, we refer to screen sessions as simply screens.

Open a New Screen

screen

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[Unit]
Description=Turn Off LED %i
After=network.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/sh -c 'echo 0 > /sys/class/leds/%i/brightness'
ExecStop=/bin/sh -c 'echo 255 > /sys/class/leds/%i/brightness'

nikolaybotev

UPSTREAM_IFACE="${1:-eth1}"

# IPv4 and IPv6

for iptables in iptables ip6tables; do
  # :INPUT
  # - returning traffic
  sudo $iptables -A INPUT -i $UPSTREAM_IFACE -m state --state ESTABLISHED,RELATED -j ACCEPT
  # - ping
  sudo $iptables -A INPUT -i $UPSTREAM_IFACE -p icmp -j ACCEPT

nikolaybotev

import { tired, sleep, eat, walk } from “my_body/index.js”;
import { pray } from “my_body/heart.js”;
import { wahtDoIKnow, why } from “my_body/brain.js”;

const knowledge = [];

function write() {
  while (!tired()) { 
    const text = knowledge.shift() || wahtDoIKnow();
    text.split(“ “).forEach(word => {

nikolaybotev

#!/bin/sh -e

# Usage: sendsms +375555555 "some text i want to send"

TELFNUMB="$1"
SMSTEXT="$2"
MODEM="${3:-/dev/ttyUSB2}"
TIMEOUT="${4:-1}"

# Text encoding

nikolaybotev

#!/bin/sh

crystalread() {
  awk -F \; '{ printf("%32s : %8.2f MB/s [%9.1f IOPS]\n", $3, $7*1024/1e6, $8) }'
}

crystalwrite() {
  awk -F \; '{ printf("%32s : %8.2f MB/s [%9.1f IOPS]\n", $3, $48*1024/1e6, $49) }'
}