OCTOBER 18, 2021

I found the following error while trying to execute PORT=4444 node ./bin/server.js on my Node.js application.

SyntaxError: Cannot use import statement outside a module

I solved it by adding the following into the package.json file of my NPM project.

  "type": "module",

SEPTEMBER 29, 2021

Nesting <a> HTML elements is forbidden. Here's an example:

<a href="">
  Go to my website, or to my
  <a href="">
    about page

A link to the about page is nested inside of a link to the root of this site.

SEPTEMBER 27, 2021

From MongoDB's JSON Schema Examples Tutorial page:

JSON Schema is an IETF standard providing a format for what JSON data is required for a given application and how to interact with it. Applying such standards for a JSON document lets you enforce consistency and data validity across similar JSON data.

The purpose of a JSON Schema is to define the allowed property names and data types allowed to facilitate the validation of a given JSON object. This reminds me of TypeScript definitions, where type-checking happens by default after you've instantiated a given interface or class.

SEPTEMBER 21, 2021

If you're trying to remove a directory using the os.rmdir function, but it contains other files, you'll probably hit the following error.

OSError: [Errno 66] Directory not empty:

You can ignore this error by using the shutil library instead of os.

import shutil

Note that Python won't prompt you to confirm this deletion action and this may lead to deleting files by mistake.

SEPTEMBER 16, 2021

When trying to stitch several videos together with FFmpeg with the following command.

ffmpeg -f concat -i list.txt -c:v copy concat.mp4

I came across this error.

[concat @ 0x7fca4281b800] Unsafe file name '2021-09-16'
list.txt: Operation not permitted

The issue, which I've been able to fix manually other times, is that there's an unsafe character one or more input video names, the space.

As it turns out, we only need to turn off this safety measure for FFmpeg to skip this check, passing the -safe 0 flag in our command.

ffmpeg -f concat -safe 0 -i list.txt -c:v copy concat.mp4

Hope that helps!

JULY 23, 2021

This page is incomplete.

I'd love to be able to export asciinema recordings as gif animations and mp4 videos. The creators don't see a point in doing this, as converting text-based recordings into image-based animations goes against asciinema's raison d'etre, but I would find it super useful to be able to include small snippets of recordings on Keynote or PowerPoint presentation slides.

JULY 15, 2021

Here are a few helper functions to list Lambda functions and layers (and to count them) using the AWS Command Line Interface (AWS CLI) to inspect the serverless resources of your Amazon Web Services (AWS) account.

Listing Lambda Layers of a Function

aws lambda get-function --function-name {name|arn} | \
jq .Configuration.Layers
    "Arn": "arn:aws:lambda:us-west-2:00000000:layer:layer-name:1",
    "CodeSize": 1231231

Counting Lambda Layers of a Function

aws lambda get-function --function-name {name|arn} | \
jq '.Configuration.Layers | length'
# Returns 1 (or number of layers attached to function)

Counting Lambda Layers in an AWS account

aws lambda list-layers | \
jq '.Layers | length'
# Returns 4 (or number of layers in your account)

Listing All Layers in an AWS account

aws lambda list-layers
    "Layers": [
            "LayerName": "layer-name",
            "LayerArn": "arn:aws:lambda:us-west-2:0123456789:layer:layer-name",
            "LatestMatchingVersion": {
                "LayerVersionArn": "arn:aws:lambda:us-west-2:0123456789:layer:layer-name:1",
                "Version": 1,
                "Description": "Layer Description",
                "CreatedDate": "2021-07-14T14:00:27.370+0000",
                "CompatibleRuntimes": [
                "LicenseInfo": "MIT"
            "LayerName": "another-layer-name",
            "LayerArn": "arn:aws:lambda:us-west-2:0123456789:layer:another-layer-name",
            "LatestMatchingVersion": {
                "LayerVersionArn": "arn:aws:lambda:us-west-2:0123456789:layer:another-layer-name:4",
                "Version": 4,
                "Description": "Layer Description",
                "CreatedDate": "2021-07-14T11:41:45.520+0000",
                "CompatibleRuntimes": [
                "LicenseInfo": "MIT"

Listing Lambda Functions in an AWS account

aws lambda list-functions
    "Functions": [
            "FunctionName": "function-name",
            "FunctionArn": "arn:aws:lambda:us-west-2:0123456789:function:function-name",
            "Runtime": "python3.7",
            "Role": "arn:aws:iam::0123456789:role/role-name",
            "Handler": "lambda_function.lambda_handler",
            "CodeSize": 1234,
            "Description": "Function description.",
            "Timeout": 30,
            "MemorySize": 128,
            "LastModified": "2021-07-14T16:48:19.052+0000",
            "CodeSha256": "28ua8s0aw0820492r=",
            "Version": "$LATEST",
            "Environment": {
                "Variables": {
            "TracingConfig": {
                "Mode": "PassThrough"
            "RevisionId": "1b0be4c3-4eb6-4254-9061-050702646940",
            "Layers": [
                    "Arn": "arn:aws:lambda:us-west-2:0123456789:layer:layer-name:1",
                    "CodeSize": 1563937
            "PackageType": "Zip"

JULY 8, 2021

This page is incomplete

An option is to set CACHE=array on your .env file.

I need to learn why this happens and what other alternatives there are to avoid this error.

This happened to me when installing laravel-geoip

It makes sense that you don't want to change your cache type if you're using file or database to array simply to use a function in this package.

Other users recommended to publish tarenn/geoip's config file and disable caching and tagging.

# Publish the configuration file
php artisan vendor:publish --provider="Torann\GeoIP\GeoIPServiceProvider" --tag=config
# Copied File [/vendor/torann/geoip/config/geoip.php] To [/config/geoip.php]
# Publishing complete.
    // ...
    'cache' => 'none', // defaults to 'all'
    // ...
    'cache_tags' => [], // defaults to // ['torann-geoip-location']
    // ...

Another option is to conditionally set the tag.

    // ...
    'cache_tags' => env('CACHE_DRIVER') == "array" ? ['torann-geoip-location'] : null,
    // ...

JUNE 30, 2021

I get this error after running docker run --rm -it IMAGE_TAG.

The problem was that the image I was using wasn't really an image to execute in Docker but a set of steps to build a Python wheel package (.whl).

The solution was to only build the image specifying an --output directory to which the resulting wheel file could be copied.

DOCKER_BUILDKIT=1 docker build --output folder_to_save_wheel .

JUNE 19, 2021

To avoid ImageMagick from interpolating pixels when you want a sharp resize method (equivalent to PIL's Image.NEAREST_NEIGHBOR) you can use mogrify and set the -filter to point.

# Assuming we're upscaling an image smaller than 2000x2000 pixels
mogrify -resize 2000x2000 -filter point image.png

MAY 17, 2021

dyld: Library not loaded: /usr/local/opt/openldap/lib/libldap-2.4.2.dylib
dyld: Library not loaded: /opt/homebrew/opt/icu4c/lib/libicuio.68.dylib
  Referenced from: /opt/homebrew/bin/php
  Reason: image not found
zsh: abort      composer

Install (or update) the Xcode developer tools.

xcode-select --install

Reinstall icu4c.

brew reinstall icu4c

Make sure no errors prevent Homebrew from installing icu4c properly. For instance, I had to remove a few php folders and re-run the brew reinstall icu4c command.

sudo rm -rf /opt/homebrew/Cellar/php@7.4/7.4.15
sudo rm -rf /opt/homebrew/Cellar/php/8.0.2

MAY 13, 2021

Here's a way to map a given color in a Pillow image (PIL.Image) to another color. This is not the fastest method and it will only replace exact matches.

In this example, we're turning all black pixels in the input image (0,0,0) with blue (0,0,255).

from PIL import Image
import numpy as np

img ='/path/to/image.png')
img[np.where((img==[0,0,0]).all(axis=2))] = [0,0,255]

MAY 13, 2021

from PIL import Image

img ='/path/to/image')

left = 10
top = 20
right = 10
bottom = 20

img = img.crop((left, top, right, bottom))

MAY 13, 2021

import json

file = open('my-file.json')
obj = json.load(file)

MAY 8, 2021

After CVAT is running and you have access to its login screen, you need to have an admin account to log in and access the admin panel.

You create an admin user from the command-line interface.

docker exec -it cvat bash -ic 'python3 ~/ createsuperuser'

This command will as you for a username, email, and password.

After you log in, you can hover your username (in the top-right corner of the screen) and select "Admin page" to access the Django admin panel, where you can manage your CVAT site, manage users, groups, and more.

MAY 1, 2021

When you use two-factor authentication to sign in to your Gmail account (or to "Sign in with Google") you access your account with your email, password, and a verification code generated by Google Authenticator or other authenticator apps (such as Duo).

You might get an error like the one that follows when trying to sign in to Gmail with your Google password.

Authentication failed. Please check your username/password and Less Secure Apps access for
Server returned error: "534-5.7.9 Application-specific password required. Learn more at 534 5.7.9 l25sm248619lfe.188 - gsmtp , code: 534"

When the service you're trying to use your Gmail account with doesn't allow you to "Sign in with Google," you need to create an app-specific password as detailed in the support Url provided by the error message.

Create a Google App Password

This app password

  • Go to your Google account
  • Security
  • Sign in to Google
  • App passwords
  • Choose the service type — e.g., Mail, Calendar, Contacts, YouTube, or Other (custom)
  • Choose the device type — e.g., iPhone, iPad, Mac, Windows, etc.
  • Generate

You'll get an app-specific password like this one — dbkdwckcplvgaktc — that will let you log in to the authorized service with your email and this password.

In my case, I use this password to be able to "Send as" from Gmail from an email address that has two-factor authentication turned on.

APRIL 28, 2021

import torch

APRIL 20, 2021

cd /path/to/repo.git
sudo chgrp -R {groupname} .
sudo chmod -R g+rwX .
find . -type d -exec chmod g+s '{}' +



If you're receiving this error when trying to composer install.

Your GitHub OAuth token for contains invalid characters

Updating Composer

2021.05.20 · Update

The solution is to update Composer to the latest version, which supports the new token format, as suggested by Jordi Boggiano on this tweet. "Composer 1.10.21 and 2.0.12 (both released April 1st) added support for the new GitHub token format."

As of this writing, the following command will install the latest version of Composer on your machine (i.e., 2.0.13). Note that future Composer updates will break the script as shown here, as the hash check won't pass.

php -r "copy('', 'composer-setup.php');"
php -r "if (hash_file('sha384', 'composer-setup.php') === '756890a4488ce9024fc62c56153228907f1545c228516cbf63f885e036d37e9a59d27d63f46af1d4d07ee0f76181c7d3') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"
php composer-setup.php
php -r "unlink('composer-setup.php');"

On macOS, you can use Homebrew to install (or reinstall) composer.

brew install composer
brew reinstall composer

The brute-force fix


As I mentioned above, both Lukas Kahwe Smith and Jordi Boggiano discouraged tinkering with Composer's auth.json file manually and recommended upgrading Composer to its latest version instead.

Still, here's the brute-fox fix that worked for me. Apparently, editing the auth.json is the only way to update to the latest Composer programmatically, and you can revert it to its original state if you opt for this option. The alternative, of course, is to upgrade as shown above.

Edit the composer authentication configuration file ~/.composer/auth.json.

nano ~/.composer/auth.json

Then replace the following.

  "github-oauth": {
    "": "ghp_[YOUR-PERSONAL-TOKEN]"

With this (basic auth):

  "http-basic": {
    "": {
      "username": "[YOUR-GITHUB-USERNAME]",
      "password": "ghp_[YOUR-PERSONAL-TOKEN]"



To Lukas Kahwe Smith and Jordi Boggiano for pointing this out on Twitter.

APRIL 20, 2021

I found this error while trying to update and install composer packages with composer install.

could not find driver (SQL: select * from information_schema.tables where table_schema = folio_burns and table_name = folio_items and table_type = 'BASE TABLE')

At first, I thought the solution was to edit /etc/php/7.4/cli/php.ini (for PHP-FPM 7.4 in my case) and uncomment the line ;extension=pdo_mysql to be like extension=pdo_mysql . But I was still getting this error as the mysql extension was missing.

PHP Warning:  PHP Startup: Unable to load dynamic library 'pdo_mysql' (tried: /usr/lib/php/20190902/pdo_mysql (/usr/lib/php/20190902/pdo_mysql: cannot open shared object file: No such file or directory), /usr/lib/php/20190902/ (/usr/lib/php/20190902/ cannot open shared object file: No such file or directory)) in Unknown on line 0

The solution ended up being to install the extension, which would also add its own .ini file and activate itself on installation.

sudo apt-get install -y php7.4-mysql

Note that you can run this command with multiple extensions to be installed at once.

sudo apt-get install -y php7.4-{xml,bcmath,gd,mbstring,xsl,zip,curl,mysql}

APRIL 15, 2021

After downloading a website as HTML with cURL or any other workflow, you can convert the HTML code to the Markdown syntax with pandoc.

pandoc -o input.html

APRIL 15, 2021

You can download any website as an HTML file (without the site's assets) using cURL in the command line, using the -L flag to follow any existing redirects.

curl -L --output nono-ma.html

The manual alternative is to right-click on a website on your browser of choice (say, Google Chrome or Firefox), select Save As.., and save the site as HTML with some of its assets in a subfolder.

Afterwards, you can convert the downloaded HTML page into a Markdown document with pandoc.

APRIL 14, 2021

Here's how to get the raw String value of a Stringable object. Laravel's Illuminate\Support\Stringable has lots of helper functions, but sometimes you want to get the raw string value. For that, you just need to use the strval PHP built-in function on an object of the Stringable class.

// Define Strintable object
$stringable = Str::of('laravel-stringable-to-string');
get_class($stringable); // returns Illuminate\Support\Stringable
gettype($stringable); // returns object

// Get its raw String value
$string = strval($stringable);
get_class($string); // returns PHP Warning:  get_class() expects parameter 1 to be object, string given in […]
gettype($string); // returns string

MARCH 28, 2021

I got a sudden fan shut down every time I would switch on my MacBook Pro (16-inch, 2019) after I upgraded macOS from Catalina to Big Sur. Here's how I fixed it.

  • CMD + R - Press on reboot to enter Rescue Mode
  • Login as a user you know the password for.
  • Utilities › Terminal
  • Run kmutil trigger-panic-medic --volume-root /Volumes/Macintosh\ HD
  • Start the computer normally

This is the Kext extension that, apparently, was causing the issue.

cd /System/Library/Extensions/AppleThunderboltNHI.kext

MARCH 19, 2021

If you're getting this message when encrypting files with a GnuPG—the GNU Pretty Good Privacy (PGP) package—you can mark your key as trusted (if that's the case). This often happens when you copy a trusted key from one machine to another.

Here's what I was getting before 'trusting' my own key.

gpg: <KEY_ID>: There is no assurance this key belongs to the named user
It is NOT certain that the key belongs to the person named
in the user ID.  If you *really* know what you are doing,
you may answer the next question with yes.

Use this key anyway? (y/N) y

Every time, I'd have to answer y to complete the encryption process.

I learned how to skip this step from this StackOverflow post.

gpg --edit-key <KEY_ID>
gpg › trust

Then you set the degree to which you trust the specified key.

1 = I don't know or won't say
2 = I do NOT trust
3 = I trust marginally
4 = I trust fully
5 = I trust ultimately
m = back to the main menu

I selected 5 as this is a key I created for myself.

Your decision? 5
Do you really want to set this key to ultimate trust? (y/N) y

Confirm, then quit.

gpg › quit

Now you can use your GPG key without confirm every operation.

MARCH 8, 2021

If you multiple Vue components of the same type throughout your application but they're not in the same parent DOM element, mounting them may not be as easy as calling their parent.

Mounting multiple Vue components with a shared parent

In this first example, we can mount all of our button-counter components by mounting their parent, #button-container.

<div id="button-container">

We just need to make one call.

new Vue({ el: '#button-container' });

But what if our components are spread throughout different HTML elements?

Mount multiple Vue components without a shared parent

Imagine you have components of the same (or different) types spread throughout your website's DOM.




We can iterate through the DOM elements and mount them one by one.

// Obtain all button-counter elements
let elements = document.getElementsByTagName('button-counter');

// Convert HTMLCollection to array
let arr = elements )

// Loop through array and mount all elements
arr.forEach((el) => {
    new Vue( { el });

Note that we had to convert the HTMLCollection to a JavaScript array before we could call the .forEach() function to iterate over the button-counter host DOM nodes.

This works with Vue 2, and Vue 3 recently released new features for multi-root components and optional TypeScript support.

MARCH 8, 2021

Change this.

window.Vue = require('vue');

For this.

window.Vue = require('vue').default;

Then this should work.

window.Vue = require('vue').default;
window.VueResource = require('vue-resource');

MARCH 8, 2021

When trying to use the newest features of Laravel 8.x to automatically install Babel plugins with the .vue() call after using mix.js(), I kept getting the following error.

AssertionError [ERR_ASSERTION]: mix.js() is missing required parameter 1: entry

Even though I was using Laravel 8.x, my application had been migrated from older versions and my JavaScript dependencies in package.json were old. Specifically, I was still using Laravel Mix 5 while the newest version 6 had been released.

The solution was to change to version ^6.0.6 in package.json and run npm install, as the .vue() call is a new feature in Laravel Mix 6.

    "devDependencies": {
        // ...
        "laravel-mix": "^6.0.6",
        // ...

Then on webpack.mix.js.

mix.js('resources/js/app.js', 'public/js')

I could then run the following commands successfully.

npm run dev
npm run watch
npm run hot
npm run prod

I believe this works with Vue 2 and Vue 3, and that the Vue version wasn't the problem but the version of Mix. (Note that I had also run npm update previously to update other dependencies and had to remove the --inline, --hide-modules and --no-progress options from my development and production commands in the scripts property of package.json.)

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