Markus Schicker appcoders

Better SSH Authorized Keys Management

A seemingly common problem that people encounter is how to handle all of your users authorized_keys file.

People struggle over management, ensuring that users only have specific keys in the authorized_keys file or even a method for expiring keys. A centralized key management system could help provide all of this functionality with a little scripting.

One piece of functionality overlooked in OpenSSH is the AuthorizedKeysCommand configuration keyword. This configuration allows you to specify a command that will run during login to retrieve a users public key file from a remote source and perform validation just as if the authorized_keys file was local.

Here is an example directory structure for a set of users with SSH public keys that can be shared out via a web server:

Ubuntu Grub Boot Kernel

Boot a specific installed Ubuntu kernel using grub-reboot and grub-set-default.

This allows you to pick what kernel you want to boot on next reboot, or set the default, without having to know much about how grub works or editing config files.

Usage

  Usage: boot-kernel [options] [kernel]

call grub-reboot or grub-set-default to boot the provided kernel.

Do not use forEach with async-await

TLDR: Use for...of instead of forEach() in asynchronous code.

For legacy browsers, use for(...;...;...) or [].reduce()

To execute the promises in parallel, use Promise.all([].map(...))

The problem

How to disable cloud-init in Ubuntu

Prevent start

Create an empty file to prevent the service from starting
```
  sudo touch /etc/cloud/cloud-init.disabled
```

Uninstall

Setup a Node.js project with Typescript, ESLint, Prettier, Husky

Starting a personal node project could be easy; starting a team node project could be challenging.

I am a developer currently working in SEEK Australia.

In my experience, common mistakes developer make when starting a projects are:

No Linting

	#!/bin/bash

	#### This script is published by Philipp Klaus <[email protected]>
	#### on <http://blog.philippklaus.de/2011/05/ipv6-6in4-tunnel-via-hurricane-electric-tunnelbroker-net-automatic-ip-update-on-mac-os-x/>
	#### It is originally by freese60 and modified by limemonkey.
	#### Found on <http://www.tunnelbroker.net/forums/index.php?topic=287.0>

	### Uncomment this line to debug the script:
	#set -x

	global
	maxconn 4096 # Total Max Connections. This is dependent on ulimit
	nbproc 2
	log 127.0.0.1 local1 notice

	defaults
	mode http
	log global

	frontend all 0.0.0.0:80

	#import <XCTest/XCTest.h>

	@interface AsyncTestingPrimer : XCTestCase

	@end

	@implementation AsyncTestingPrimer

	/*
	* This is how not to test async calls

	#!/bin/bash

	if [[ "x${1}" == "x" ]]; then
	dir="."
	else
	dir="${1}"
	fi

	# Based on https://stackoverflow.com/questions/10575665/linux-find-command-find-10-latest-files-recursively-regardless-of-time-span
	# with additions to return only the date of the newest file

	#!/bin/bash

	# dependencies:
	# curl
	# culicue - curl wrapper to make oauthv1 requests (https://github.com/decklin/curlicue/blob/master/curlicue)
	# jq - filter json from twitter api and transform to a structure mattermost is expecting

	# credentials file can be created with the curlicue-setup script
	credentials=/home/me/credentials.conf
	webhook='https://yourmattermost.server/hooks/1mjxx6amd52q8doxzy16o75adh'