Advanced Bash-Scripting Guide

• Linux

An in-depth exploration of the art of shell scripting

Bash Guide for Beginners

• Linux

This is a practical guide which, while not always being too serious, tries to give real-life instead of theoretical examples.

BASH Programming - Introduction HOW-TO

• Linux

Introduction guide

Bash Reference Manual

• Linux

This text is a brief description of the features that are present in the Bash shell. This manual is meant as a brief introduction to features found in Bash. The Bash manual page should be used as the definitive reference on shell behavior.

Clker

Free clipart for a wide range of uses

crontab guru

• Linux

The quick and simple editor for cron schedule expressions

Gnome

• Linux

An easy and elegant way to use your computer, GNOME is designed to put you in control and get things done.

Google Fonts

• Linux
• HTML

Google Fonts is a library of more than 1,000 free licensed font families and APIs for convenient use via CSS and Android. The library also has delightful and beautifully crafted icons for common actions and items. Download them for use in your digital products for Android, iOS, and web.

GPS Babel

GPSBabel converts waypoints, tracks, and routes between popular GPS receivers such as Garmin or Magellan and mapping programs like Google Earth or Basecamp.

HTML and CSS Border Wizard

• HTML

Help to create a desired border style

HTML Help

• HTML

Reference and help information for HTML and CSS.

Internet Archive

Internet Archive is a non-profit library of millions of free books, movies, software, music, websites, and more.

IP2Location

• favorite
• IPFire

Download a list of IPs by country. Usually used for iptables or other firewall blocking.

Linux Cookbook

• Linux

Linux Tips and Techniques for Everyday Use

Linux Tutorial

• Linux

"The place where you learn Linux"

Looking for an in-depth and easy-to-understand introduction to Linux? Then look no further!
We don't just show you how to execute a handful of commands and use a few utilities. The Linux Tutorial goes beyond the basics, providing you with the knowledge necessary to get the most out of your Linux system.

Markup Validation Service

• HTML

This validator checks the markup validity of Web documents in HTML, XHTML, SMIL, MathML, etc.

Matomo

Your one stop web analytics problem solver. Matomo has revolutionised what an all-in-one web analytics platform should be.

• Powerful Web Analytics Platform
• Heatmaps, Sessions Recordings, A/B Testing, Funnels, Goals, Form Analytics
• Visitor Profiles
• Enhanced SEO Features
• Matomo Tag Manager
• GDPR Manager
• Roll-Up Reporting
• White Label

Qualys SSL Server Test

• Linux

Detailed validation of server SSL certificates and settings. Evaluate a web site.

Regular Expression Tool

• Linux

JavaScript based. Performs real time tests on a given regex expression

SMTP Diagnostics

This test will connect to a mail server via SMTP, perform a simple Open Relay Test and verify the server has a reverse DNS (PTR) record.  It will also measure the response times for the mail server.  If you don't know your mail server's address, start with a MX Lookup.