Today I responded a Tweet asking on what was the regex for a particular scenario:


I wrote it quickly without testing, after I got my coffee ready, I thought on how I would test this regular expression, I found several ways on doing that, this is what this post is about, how to quickly test your regular expressions to see if they are correct or not.

1. Google and search for “regex tester online”

Whichever result you pick, it should work, I always pick the first result, right now is


Hi there! this will be a quick-short blog post about Bash, specifically about one of the coolest bash builtins, local.

I wanted to clarify a few things about this shell builting that, I feel most of the Bash developers don´t pay attention to, they seem to ignore control variables from the equation and only use the builtin with explicit variables. I saw two cases this week, I code-reviewed a bunch of Bash code at the place I work and I just sent a Pull Request suggesting an improvement involving local:

¡Hola! El otro día me puse a pensar que quizás sería de beneficio, para mí y para alguien más, plasmar las ideas que va leyendo uno, y qué mejor que un post, el beneficio será que esto me empujará a estructurar mejor mis ideas, expandirlas, abrir debate y quizás a uno que otro le resulte interesante o de beneficio el contenido. La finalidad es no dejar la idea fermentándose o cuajada en la cabeza, soltarla y ver qué eco genera. …

Special Pythagorean, largest palindrome, and more

Image of cartoon bear.
Image of cartoon bear.
Source: Google

Hello. In this article, I would like to show you my learnings while solving the first 15 Project Euler problems in Golang. The solutions for the problems are all available at:

Project Euler

First of all, what is Project Euler? Simply put, it is a website with mathematical and computer science problems. It, basically, gives you a problem description and you need to enter the right answer as shown in the following image:

Hello! In this article, I will show you multiple easy ways to customize the default Spring Boot Banner.

I am currently working on a small Web Application using Spring Boot, after running my app for dozen of times while testing, I wondered how I could show a different banner instead of the default:

Write better Bash scripts with this template

decorative: abstract pattern of black lines on white background
decorative: abstract pattern of black lines on white background
Photo by Ussama Azam on Unsplash

In this article, I will show you the safe Bash script template I have used for several years in production environments with great results. You will be able to adapt the code easily for your use case.

This is what the Bash template covers:

  • A shebang focused on portability: #!/usr/bin/env bash
  • The fail-fast principle with the set -o errexit. Don’t worry if you don’t know what any of these options are — I will explain them later.
  • Correct handling of the working directory
  • Clean up resources and files when we are done
  • Help / Usage function
  • Long options, for example…

Home Office

Muchas empresas de las llamadas, de la vieja guardia (u oldschool), tuvieron que innovar y cambiar sus procesos para soportar el llamado Home Office, podríamos decir que fue una de las bonanzas de la pandemia. Actualmente trabajo en IT, y la empresa al ver los buenos resultados que estábamos teniendo con el modelo Home Office, comenzó a pensar en permitir trabajar remotamente varios días por semana, ¡Viva la flexibilidad! Todos contentos por que se hablaba de permitirnos trabajar remotamente 2 o 3 días (los días que nosotros eligieramos) y los restantes en la oficina, hasta ahí todo perfecto, yo imagino…

Virtual meeting

Una de las cosas que los managers o gerentes tenemos que hacer de vez en cuando, es reunirnos con cada una de las personas de nuestro equipo y tratar temas como career path, ajustar tareas, ayudarles con cualquier obstáculo que enfrenten y básicamente ver las necesidades de cada uno, pero sobre todo, construir una relación con la persona utilizando la empatía. Antes de la pademia, podíamos caminar los dos juntos a la sala de reuniones mientras platicabamos de cualquier sinsentido o simplemente las bromas se daban de manera natural, todo esto en el ambiente más relajado posible. …

Let’s try the new “embed” feature we are going to have in the Go 1.16 release. These will be very basic examples but will get you a grasp on how to use this great feature, we will also check how to use the embed.FS file system, symlinks (and hardlinks…), how to read multiple files or directories, wildcards and what a linter says about our code.

First, create a file that we can reach from our program:

0 🐧 leo@lein ~/go-embed $ cat hello.txt 

A simple text file with two lines. To embed this file in our Go program…

Hello, in this little post I would like to show you how you can use Makefiles to ease the development of your Golang programs.

“go <command>s” are great by themselves, you can basically manage every part of your Golant development phase with Go’s native tools, so why would I want to use something else? This is a fair question. In many cases I have had the necessity of sharing my codebases or repositories with someone that is not familiar with Golang itself, they won’t know how to build it. Of course you can attack that problem with some documentation in…

Leo Gutiérrez

Hi! I am Leonardo Gutiérrez R., a passionate software developer, I hope you find the content in this blog interesting. I write about IT related stuff.

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