The difference between a Slice and an Array in Rust

In Rust, a slice is a reference to a contiguous section of a larger data structure, such as an array or a vector. It is represented using the syntax &[T], where T is the type of the elements in the slice. A slice does not own the data it refers to, it just provides a […]

How to build your Docker image using the same Dockerfile regardless of the host architecture

Problem If you are now using docker on a Mac M1 (arm64 platform), you don’t want to use amd64 as the architecture for your Linux Images. You could have 2 lines on your Dockerfile and comment each one depending on where you’re building the image Dockerfile # Building on Apple Silicon host FROM –platform=linux/arm64 ubuntu:20.04 […]

Here’s my first very rough draft of “LifeTips”.

https://github.com/gubatron/LifeTips#life-tips It is a short manuscript with actionable tips to live a better life, it’s there primarily as a manual for my kids when I die. Advice is grouped into 6 sections:– TIME– BODY– MIND– MONEY– WORK/LEADERSHIP (Entrepreneurship)– PEOPLE Most needed and valuable feedback is welcome. If you have corrections, additions, feel free to Create […]

How to resize AWS ec2 ebs root partition without rebooting in 3 steps

Go to the AWS EBS dashboard and modify the volume size. Might be good to create a snapshot of it for safety but haven’t really failed ever doing this. # 1. Check the device of your partition $ sudo lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS loop0 7:0 0 28.1M 1 loop /snap/amazon-ssm-agent/2012 loop1 […]

Removing duplicate records from a table in Sqlite3 when “DELETE” doesn’t support “LIMIT 1”

Accessing and manipulating a 32bit integer as a byte array in C++ using unions

I don’t think I’ve ever used union for anything, but today I came across a very interesting use case to avoid bit-shifting tricks when dealing with data embedded in numbers. What’s a union? Microsoft defines it this way A union is a user-defined type in which all members share the same memory location. This definition means that […]

Things to remember when compiling/linking C/C++ software

Things to remember when compiling/linking C/C++ software by Angel Leon. March 17, 2015; Updated August 29, 2019. Updated last on February 27, 2023 Include Paths On the compilation phase, you will usually need to specify the different include paths so that the interfaces (.h, .hpp) which define structs, classes, constants, and functions can be found. […]

How to enable source highlighting when doing `less mycodefile.ext`

How to enable source highlighting when doing less mycodefile.ext Install source-highlight sudo apt install source-highlight Configure it on your .bash_profile lessWithSourceHighlightSetup() { # location of the script may vary src_hilite_pipe_script=`dpkg -L libsource-highlight-common | grep lesspipe` export LESSOPEN=”| ${src_hilite_pipe_script} %s” export LESS=’ -R ‘ } lessWithSourceHighlightSetup Use it on any code file less -N /path/to/mycode.ext view […]

Pascal Triangle Generator in Python, and then in Haskell – The Gubatron Method

Here’s in python, imperatively, and then in functional style without the need for loops. This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters Show hidden characters def pascal(n): […]

Python in Functional Style: How to add 2 lists of integers without using loops

Usually you’d add a list of integers this way: [pastacode lang=”python” manual=”a%20%3D%20%5B2%2C%202%2C%202%2C%202%5D%0Ab%20%3D%20%5B2%2C%202%2C%202%2C%202%5D%0Ac%20%3D%20%5B%5D%0Afor%20i%20in%20range(len(a))%3A%0A%20c.append(a%5Bi%5D%20%2B%20b%5Bi%5D)” message=”” highlight=”” provider=”manual”/] You can do it functionally without any loops in different ways: Using map and a lambda that adds them up [pastacode lang=”python” manual=”c%20%3D%20list(map(lambda%20x%2Cy%3A%20x%2By%2C%20a%2C%20b))” message=”” highlight=”” provider=”manual”/] or you can import the add operator as a named function [pastacode lang=”python” manual=”from%20operator%20import%20add%0Ac%20%3D%20list(map(add%2C%20a%2C%20b))” […]