Chris A James Christophosaurus

security and hardening options for systemd service units

A common and reliable pattern in service unit files is thus:

NoNewPrivileges=yes
PrivateTmp=yes
PrivateDevices=yes
DevicePolicy=closed
ProtectSystem=strict

ANSI Escape Sequences

Standard escape codes are prefixed with Escape:

Ctrl-Key: ^[
Octal: \033
Unicode: \u001b
Hexadecimal: \x1B
Decimal: 27

GROKKING NOTES

I liked the way Grokking the coding interview organized problems into learnable patterns. However, the course is expensive and the majority of the time the problems are copy-pasted from leetcode. As the explanations on leetcode are usually just as good, the course really boils down to being a glorified curated list of leetcode problems.

So below I made a list of leetcode problems that are as close to grokking problems as possible.

Pattern: Sliding Window

Linux Server Setup & MERN App Deployment

These are the steps to setup an Ubuntu server from scratch and deploy a MERN app with the PM2 process manager and Nginx. We are using Linode, but you could just as well use a different cloud provider or your own machine or VM.

Create an account at Linode

Click on Create Linode

Choose your server options (OS, region, etc)

SSH Keys

Job Control in ZSH and Bash

All processes in ZSH/Bash under job control are in 3 states: foregrounded, backgrounded and suspended.

# run command in the foreground
command
# run commend in the background

	package main

	import (
	"fmt"
	"os"
	"os/exec"
	"syscall"
	)

	func main() {

	┌──────────────────────────────────────────────────────────────────────────────────────────────────────────┬──────────────────────────────────────────────────────────────────────────
	│ printf Format Specifiers │
	│ ┌──────────┬──────────────────────────────────────────────────┬───────────────────────────────────────┐ │/** printf format specifiers
	│ │ Specifier│Description │ Example Output │ │ * ███ ▄████████ ███ ▄████████ ███ █▄ ▄██████▄
	│ ├──────────┼──────────────────────────────────────────────────┼───────────────────────────────────────┤ │ *▀█████████▄ ███ ███ ▀█████████▄ ███ ███ ███ ███ ███ ███
	│ │ %d │Signed decimal integer │ printf("%d", 42); // 42 │ │

	package main

	import (
	"fmt"
	"reflect"
	)

	// Name of the struct tag used in examples
	const tagName = "validate"

	# Change these variables as necessary.
	MAIN_PACKAGE_PATH := ./cmd/example
	BINARY_NAME := example

	# ==================================================================================== #
	# HELPERS
	# ==================================================================================== #

	## help: print this help message
	.PHONY: help

	package main
	import (
	"net"
	"os"
	)

	func main() {
	strEcho := "Halo"
	servAddr := "localhost:6666"
	tcpAddr, err := net.ResolveTCPAddr("tcp", servAddr)