Dev Notes

Various Cheat Sheets and Resources by David Egan/Carawebs.

This website contains notes & cheatsheets for web development, Linux systems administration, information security and cryptocurrency.

This site is maintained by David Egan:

Highlighted Posts

Encrypted Backup Drive in Ubuntu Xenial 16.04

15 Oct 2017

Protect your sensitive data - create a LUKS encrypted backup partition for Ubuntu 16.04 Xenial Xerus that is automatically mounted on boot.

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Bitcoin Cold Wallet Setup Bash Script

22 Aug 2017

Access a Bitcoin core wallet in an airgapped environment. Secure management of cold-wallets.

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Ignore IP Addresses in Fail2Ban

20 Jul 2017

Fail2Ban can help protect your Linux server from attack. It's a Python package that monitors log files and dynamically adjusts firewall rules to block malicious IP addresses. This article shows how to configure Fail2Ban so that specified IP addresses are ignored.

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Install and Run Geth (golang implemenation of Ethereum) on Ubuntu

03 Jul 2017

Ethereum is a decentralized blockchain-based platform that runs smart contracts. Because of the decentralized nature of Ethereum, smart contracts run exactly as programmed - short of an internet apocalypse, there is no possibility of downtime, censorship, fraud or third-party interference. The network is cryptographically secure, decentralized and tamper-proof.

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Verification of Bitcoin Core Download in Ubuntu

01 Jul 2017

Install Bitcoin Core in Ubuntu 16.04 - how to download and verify from

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Enable all Apache Config Files

22 Jun 2017

Enable all Apache virtual host configurations at once. This article provides a useful BASH script that loops through and enables all vhost configs - useful when setting up new development machines or changing servers.

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Laravel 5.4 and MariaDB Errors

28 May 2017

When running migrations on Laravel 5.4 and MariaDB you may encounter an error related to the permitted maximum length of keys - "1071 Specified key was too long; max key length is 767 bytes" Fortunately, there's an easy fix.

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Apache Server Security on Ubuntu 16.04 Xenial

22 May 2017

This article lists some sensible configuration defaults for Apache 2.4 on a Ubuntu 16.04 server. It explains how to apply these globally at the server level.

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WordPress Reserved Terms and Post Requests

17 May 2017

When submitting a form to a WordPress site, there are a number of reserved keywords that should not be used as name attributes - including “name”, “author” and “type”. Using such keywords may result in odd errors - either unexplained 404 errors or the template reverting to the index.php template.

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Managing Dependencies in a Laravel Package

26 Mar 2017

When developing a custom Laravel package, you may require an additional package. This article describes how to use Composer to manage such dependencies, and how to use the custom package's service provider to make the added functionality available.

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Manage WordPress Plugins Using Composer

24 Mar 2017

Composer is a really convenient way to manage WordPress plugins. Add a couple of lines to the project `composer.json`, run `composer update` and your plugins will be set up.

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Arrow Functions in ECMAScript 6

14 Mar 2017

ES6 introduces a new syntax for writing JavaScript functions: arrow functions. Arrow function expressions have more concise syntax than a function expression.

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Reduce a Numerically Indexed Array to a Simple Array in PHP

12 Mar 2017

Reducing a numerically indexed multi-dimensional array to a simple array can be achieved easily by means of combining array_merge() with the ‘splat’ (...) operator.

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Using Composer to Manage Specific Version of a Package in a Private Repo

28 Feb 2017

According to their website, Composer is a dependency manager for PHP. While true, I think this is a bit of an understatement. I’m fairly new to Composer, but it’s revolutionising my workflow.

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Let's Encrypt & Apache on Ubuntu Xenial

25 Feb 2017

Notes and snippets on using Let's Encrypt with Apache on Ubuntu 16.04 Xenial.

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