Alexandru Nedelcu - Wiki

Bitwarden / Vaultwarden

Alexandru Nedelcu — Mon, 26 Aug 2024 10:45:19 +0000

Article updated at August 26, 2024, created at August 26, 2024.

Self-hosting (Vaultwarden)

Setup for docker-compose.yaml:

vaultwarden:
  container_name: vaultwarden
  image: vaultwarden/server:latest
  restart: always
  healthcheck:
    test: ['CMD-SHELL', 'curl --silent --fail http://localhost:80/ || exit 1']
  ports:
    - "3201:80"
  volumes:
    - vaultwarden:/data
  networks:
    - external_network
  env_file:
    - ./envs/vaultwarden.env

Related ./envs/vaultwarden.env file:

##
# Documentation:
# https://github.com/dani-garcia/vaultwarden/wiki/Enabling-admin-page
#
# To generate:
# echo -n "MySecretPassword" | argon2 "$(openssl rand -base64 32)" -e -id -k 65540 -t 3 -p 4
#
ADMIN_TOKEN=

##
# https://github.com/dani-garcia/vaultwarden/wiki/Disable-registration-of-new-users
#
SIGNUPS_ALLOWED=false

##
# https://github.com/dani-garcia/vaultwarden/wiki/SMTP-Configuration
#
# NOTE: Hetzner and other cloud providers, are blocking port 467
# https://www.fastmail.help/hc/en-us/articles/1500000278342-Server-names-and-ports
#
SMTP_HOST=smtp.fastmail.com
SMTP_PORT=587
SMTP_SECURITY=starttls
SMTP_FROM=
SMTP_USERNAME=
SMTP_PASSWORD=

##
# https://github.com/dani-garcia/vaultwarden/wiki/Enabling-Mobile-Client-push-notification
# https://bitwarden.com/host/
#
PUSH_RELAY_URI=https://api.bitwarden.eu
PUSH_IDENTITY_URI=https://identity.bitwarden.eu
PUSH_ENABLED=true
PUSH_INSTALLATION_ID=
PUSH_INSTALLATION_KEY=

My Nginx reverse proxy configuration:

root /var/www/vault.nedelcu.net;
log_not_found off;

include ./snippets/gzip.conf;

location / {
    proxy_pass http://vaultwarden;
    include ./snippets/proxy-backend.conf;
}

Where ./snippets/proxy-backend.conf is:

include ./snippets/cloudflare-ips.conf;

proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header Proxy "";
proxy_pass_header Server;

proxy_buffering on;
proxy_redirect off;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;

proxy_cache CACHE;
proxy_cache_valid 200 7d;
proxy_cache_valid 410 24h;
proxy_cache_use_stale error timeout updating http_500 http_502 http_503 http_504;

add_header X-Cached $upstream_cache_status;
tcp_nodelay on;

For ./snippets/cloudflare-ips.conf see Restoring original visitor IPs (Cloudflare.com).

CLI commands

Installation for macOS:

brew install bitwarden-cli jq

Lists items in the order they were modified:

bw list items | jq '[.[] | {name: .name, date: .revisionDate}] | sort_by(.date)'

Lists items with passkeys defined:

bw list items | jq '.[] | select(.login.fido2Credentials | length > 0) | {name: .name, id: .id, updated: .revisionDate}'

Gradle

Alexandru Nedelcu — Sat, 25 May 2024 15:27:05 +0000

Article updated at May 25, 2024, created at May 25, 2024.

Upgrading the Gradle wrapper to the latest version:

./gradlew wrapper --gradle-version latest

OCaml

Alexandru Nedelcu — Mon, 15 Apr 2024 17:23:07 +0000

Article updated at April 15, 2024, created at April 15, 2024.

Installing

For macOS (see other platforms):

brew install opam

Initialize:

opam init

# Test
opam switch

Some utilities:

# For the VS Code extension (OCaml Platform)
opam install ocaml-lsp-server

# OCaml REPL
opam install utop

# Standard library recommended by Real World OCaml
opam install core core_bench

JavaScript / TypeScript

Alexandru Nedelcu — Tue, 30 May 2023 08:05:11 +0000

Article updated at May 30, 2023, created at May 30, 2023.

Getting Started

Vite

Starting a new TypeScript + React project, using a Vite template:

npm create vite@latest name-of-your-project -- \
    --template react-ts

Webpack:

Relevant documentation:

Resources

Bulma: CSS framework;
React Router;

Scala

Alexandru Nedelcu — Sat, 20 May 2023 12:53:40 +0000

Article updated at October 6, 2023, created at May 20, 2023.

Libraries

For building UI:

tui-scala: Beautiful Text-based User Interfaces for Scala;
ScalaFX: simplifies the creation of JavaFX-based user interfaces in Scala;

For parsing command-line arguments:

Documentation

Macros:

Kotlin

Alexandru Nedelcu — Sun, 30 Apr 2023 13:07:39 +0000

Article updated at January 28, 2025, created at April 30, 2023.

Resources

Kotlin-specific:

Arrow: Functional companion to Kotlin’s Standard Library;
kotlinx.serialization: Kotlin multiplatform / multi-format serialization;
Ktor: HTTP client/server library;
SQLDelight: Generates type-safe Kotlin APIs from SQL;
kotlinx-gettext: I18N library;

CLI:

clikt: Multiplatform command line interface parsing for Kotlin;
kotter: A declarative, Kotlin-idiomatic API for writing dynamic console applications;

UI, Kotlin/JS:

kotlin-wrappers: wrappers for popular JavaScript libraries;
kvision: web UI framework for Kotlin, alternative to React;
- kvision-io (GitHub): source code for a presentation website built in Kotlin, useful sample of a Webpack configuration that integrates Sass and Bulma;
kobweb: A modern framework for full stack web apps in Kotlin, built upon Compose HTML;
compose-multiplatform: modern UI framework for Kotlin that makes building performant and beautiful user interfaces easy and enjoyable;

Samples:

Uncancelable, like in Cats-Effect;
- Using UncancellableRegion;

Multiplatform

klibs.io: browse multiplatform libraries
KMP project wizard

Kotlin/JS — FAQ

Integrate SASS/CSS files in the Webpack build

Declare a require function:

@JsName("require")
external fun jsRequire(name: String): dynamic

Declare dependencies in build.gradle.kts:

implementation(devNpm("sass", "^1.62.1"))
implementation(devNpm("sass-loader", "^13.2.2"))

For configuring Webpack, create a file webpack.config.d/css.js:

config.module.rules.push({
    test: /\.css$/,
    use: [
        "style-loader",
        {
            loader: "css-loader",
            options: {sourceMap: false}
        }
    ]
});

And another file at webpack.config.d/sass.js:

config.module.rules.push({
    test: /\.s[ac]ss$/,
    use: [
        "style-loader",
        {
            loader: "css-loader",
            options: {sourceMap: false}
        },
        "sass-loader"
    ]
});

We can also declare external dependencies on CSS frameworks, such as Bulma:

implementation(npm("bulma", "^0.9.4"))

Create src/main/resources/sass/main.scss:

@import '~bulma/bulma';

html {
  background-color: antiquewhite;
}

Then in src/main/kotlin/main.kt:

fun main() {
    jsRequire("./sass/main.scss")
}

Reference: Slack conversation.

Custom HTML attributes in the kotlin-react DSL

When using the React DSL from kotlin-wrappers:

import react.dom.html.AnchorHTMLAttributes
import react.dom.html.HTMLAttributes

operator fun HTMLAttributes<*>.get(key: String): String? =
    asDynamic()[key]

operator fun HTMLAttributes<*>.set(key: String, value: String?) {
    if (value == null)
        asDynamic().removeAttribute(key)
    else
        asDynamic()[key] = value
}

var AnchorHTMLAttributes<*>.dataTarget: String?
    get() = this["data-target"]
    set(value) { this["data-target"] = value }

//...
import react.dom.html.ReactHTML as html

html.a {
    dataTarget = "siteNavBar"
    //...
}

Reference: kotlin-wrappers#1788.

Rclone

Alexandru Nedelcu — Mon, 23 Jan 2023 11:34:49 +0000

Article updated at January 26, 2023, created at January 23, 2023.

Install (macOS)

This is required for getting mount to work properly, see:

Run:

brew install --cask macfuse

brew install gromgit/fuse/rclone-mac

Mount (OneDrive)

#!/usr/bin/env bash

LOG_PATH="$HOME/Library/Logs/rclone-onedrive-mirror.log"
MOUNT_DIR="$HOME/Library/CloudStorage/OneDrive"
mkdir -p "$MOUNT_DIR"

/usr/local/opt/rclone-mac/libexec/rclone/rclone mount \
    onedrive: "$MOUNT_DIR" \
    --volname "OneDrive" \
    --buffer-size 64M \
    --vfs-read-ahead 512M \
    --vfs-cache-mode full \
    --vfs-cache-max-age 8760h \
    --vfs-cache-max-size 100G \
    --vfs-cache-poll-interval 30s \
    --vfs-write-back 5s \
    --attr-timeout 8700h \
    --dir-cache-time 8760h \
    --poll-interval 30s \
    --log-level INFO \
    --log-file "$LOG_PATH"
    # Optional:
    # --rc \
    # --rc-web-gui \
    # --rc-web-gui-no-open-browser \
    # --rc-htpasswd "$HOME/.config/rclone/htpasswd"

# Optionally, inform the user when the process stops.
# Requires: brew install terminal-notifier
PROC_EXIT_CODE="$?"
terminal-notifier -title "OneDrive mount stopped!" -message "$LOG_PATH"
exit $PROC_EXIT_CODE

Notes:

Web interface is served at http://127.0.0.1:5572/, see: Remote controlling rclone with its API;
For the cache options used, see: VFS File Caching;

For serving the remote control web UI, you need credentials:

touch ~/.config/rclone/htpasswd
htpasswd -B ~/.config/rclone/htpasswd alex

macOS service

The above command supports a --daemon option, but I’d like automatic launch at startup, maybe even restarts. Create a script in ~/bin/mount-onedrive:

Create ~/Library/LaunchAgents/my.rclone-onedrive-mount.plist:




  
    KeepAlive
    
    Label
    my.rclone-onedrive-mount
    ProgramArguments
    
      /Users/myname/bin/mount-onedrive
    
    RunAtLoad
    
    UserName
    myname

The service can then be loaded via:

launchctl load -w ~/Library/LaunchAgents/my.rclone-onedrive-mount.plist

Or unloaded via:

launchctl unload ~/Library/LaunchAgents/my.rclone-onedrive-mount.plist

Bisync

Alternatively there’s a bisync command.

On first run, the database needs to be initialized, via --resync, but as a warning, this can override the files of “path2” with those of “path1”.

This is the onedrive-sync-init script:

#!/usr/bin/env bash

function notifyIfError() {
    PROC_EXIT_CODE="$1"
    if [ "$PROC_EXIT_CODE" -ne 0 ]; then
        terminal-notifier -title "OneDrive sync failed!" -message "Check the logs"
        echo "OneDrive sync failed"
        exit "$PROC_EXIT_CODE"
    fi
}

mkdir -p ~/OneDrive/Bisync
mkdir -p ~/OneDrive/.db

rclone bisync onedrive: ~/OneDrive/Bisync \
    --resync \
    --filters-file ~/.config/rclone/onedrive-filter.conf \
    --workdir ~/OneDrive/.db \
    -v "$@"
notifyIfError "$?"

# Adds .rclone-check files in the top sub-directories
find ~/OneDrive/Bisync -type d -d 1 -exec touch "{}/.rclone-check" \;
notifyIfError "$?"

# Syncs those .rclone-check files
rclone bisync onedrive: ~/OneDrive/Bisync \
    --filters-file ~/.config/rclone/onedrive-filter.conf \
    --workdir ~/OneDrive/.db \
    -v "$@"
notifyIfError "$?"

This is the onedrive-sync-periodic script, which could be installed in crontab:

#!/usr/bin/env bash

rclone bisync onedrive: ~/OneDrive/Bisync \
    --check-access \
    --check-filename ".rclone-check" \
    --filters-file ~/.config/rclone/onedrive-filter.conf \
    --workdir ~/OneDrive/.db \
    -v "$@"

PROC_EXIT_CODE="$1"
if [ "$PROC_EXIT_CODE" -ne 0 ]; then
    terminal-notifier -title "OneDrive sync failed!" -message "Check the logs"
    echo "OneDrive sync failed"
    exit "$PROC_EXIT_CODE"
fi

And then there’s the ~/.config/rclone/onedrive-filter.conf file, which dictates what to sync (aka selective sync):

- **/.DS_Store
- **/.localized
- **/*.swp

+ /Documents/**
+ /Scanned/**
+ /Screenshots/**

# Exclude everything by default
- **

Web Design

Alexandru Nedelcu — Tue, 13 Dec 2022 13:04:51 +0000

Article updated at December 13, 2022, created at December 13, 2022.

Resources

Bootstrap: ready-made generic CSS;
SVGrepo.com: collection of SVG Icons;
CSS filter generator: for colorizing images;

Bookmarklets

Alexandru Nedelcu — Sun, 04 Dec 2022 10:01:00 +0000

Article updated at March 4, 2025, created at December 4, 2022.

About

Samples are meant for the bookmarklet generator (just a simple HTML+JS file), that generates code compatible with Firefox for Android (as the latter has issues with the classic window.open, which has to be avoided).

Bluesky

URL (page URL and title):

https://bsky.app/intent/compose?text=%22%t%22%0A%0A%s

👉 Generate bookmarklet

Mastodon

URL used (both page title and URL):

https://mastodon.social/share?text=%22%t%22%0A%0A%s

👉 Generate bookmarklet

URL (just page URL):

https://old.reddit.com/submit?url=%s

👉 Generate bookmarklet

URL (just page URL):

https://www.linkedin.com/sharing/share-offsite/?url=%s

👉 Generate bookmarklet

Facebook

URL used (just page URL):

https://www.facebook.com/sharer.php?src=bm&v=4&i=1628766166&u=%s

👉 Generate bookmarklet

𝕏/Twitter

URL used (both page title and URL):

https://x.com/intent/tweet?text=%22%t%22%0A%0A%s

👉 Generate bookmarklet

Subscribing

Linkding

See homepage.

URL:

https://my.linkding.host/bookmarks/new?url=%s&title=%t&auto_close

👉 Generate bookmarklet

FreshRSS

URL:

https://my.freshrss.host/i/?c=feed&a=add&url_rss=%s

👉 Generate bookmarklet

NewsBlur

URL:

https://www.newsblur.com/?url=%s

👉 Generate bookmarklet

Mastodon

Alexandru Nedelcu — Tue, 22 Nov 2022 09:55:19 +0000

Article updated at October 9, 2024, created at November 22, 2022.

Twitter migration

WARN: Mastodon ain’t Twitter. Its design and available features are slightly different, as a matter of philosophy.

Instances

Mastodon is “federated”. At joinmastodon.org you can find a list of instances available, but it’s not complete.

It’s a good idea to prefer alternatives to mastodon.social, because this server is being hammered by new traffic. On the other hand, instances are servers maintained by volunteers, so it’s best to find some properly maintained ones.

For professionals in the software industry, these instances seem to be pretty good:

fosstodon.org (English-only)
hachyderm.io

Some smaller instances you might want to consider:

Getting started resources

Available apps

The website works well on mobile too;
On Android, the official app isn’t very good for now, prefer Tusky;
See list of available apps;

Utilities

Browser extension that redirects you from Mastodon4 instances to your home instance (makes it easier to follow people):
mastodon4-redirect (Firefox, Chrome).

To find your Twitter friends on Mastodon:
https://fedifinder.glitch.me

For the cool factor, implement “WebFinger” on your own domain:
https://rossabaker.com/projects/webfinger/

For following Twitter’s drama, without logging into Twitter:
https://twitterisgoinggreat.com

Download Twitter archive

Download your Twitter archive and store it somewhere safe, even if you don’t plan on leaving Twitter:
https://x.com/settings/download_your_data

The archive download is fairly usable. But you might want to parse your archive, to replace t.co links and spit out markdown files:

Leaving Twitter?

First download your Twitter archive and store it somewhere safe:
https://x.com/settings/download_your_data

If you’d like to delete your Twitter account, depending on how popular your account is, you might want to avoid deleting it, to prevent impersonation/cybersquatting. I recommend to:

Download your Twitter archive;
Delete all your tweets: https://tweetdelete.net
Modify your profile to inform your visitors that you moved;
Maybe also lock your account, to prevent new followers;

Self-Hosting

I have self-hosted my own Mastodon instance at https://social.alexn.org (at the time of writing I’ve moved to https://mastodon.social/@alexelcu). This is my own configuration, tuned to my needs…

Services used

Hetzner, for a VPS with 4 GB of RAM and 40 GB of disk space; 2 GB should be fine, but it may need a swap setup; I might also need more disk space in the future, or block storage;
Cloudflare because it can save you bandwidth (must ensure correct caching setup);
Fastmail for sending emails via SMTP, as I was already using it for my personal email, and supports SMTP-only passwords;
Backblaze B2 for backups and potentially for storing cached files;

Docker (docker-compose)

version: '3.8'

services:
  redis:
    container_name: redis
    image: redis:7
    restart: unless-stopped
    command: /bin/sh -c "redis-server --appendonly yes --requirepass $$REDIS_PASSWORD"
    healthcheck:
      test: ['CMD', 'redis-cli', '-a', '$$REDIS_PASSWORD', 'ping']
    volumes:
      - redis:/data
    networks:
      - internal_network
    sysctls: # https://github.com/docker-library/redis/issues/191#issuecomment-528693994
      - net.core.somaxconn=511
    env_file:
      ./envs/redis.env

  postgresdb:
    container_name: postgresdb
    image: 'postgres:15-alpine'
    healthcheck:
      test: ['CMD', 'pg_isready', '-U', 'postgres']
    volumes:
      - 'postgres-db:/var/lib/postgresql/data'
    restart: unless-stopped
    env_file:
      - ./envs/postgres.env
    networks:
      - internal_network

  mastodon-web:
    container_name: mastodon-web
    image: 'ghcr.io/mastodon/mastodon:latest'
    command: 'bash -c "bundle exec rake db:migrate && rm -f /mastodon/tmp/pids/server.pid && bundle exec rails s -p 3000"'
    ports:
      - 3000:3000
    restart: unless-stopped
    healthcheck:
      test: ['CMD-SHELL', 'wget -q --spider --proxy=off localhost:3000/health || exit 1']
    volumes:
      - 'mastodon-volume:/mastodon/public/system'
    env_file:
      - ./envs/mastodon.env
    depends_on:
      - postgresdb
      - redis
    networks:
      - internal_network
      - external_network

  mastodon-sidekiq:
    container_name: mastodon-sidekiq
    image: 'ghcr.io/mastodon/mastodon'
    command: 'bundle exec sidekiq'
    restart: unless-stopped
    healthcheck:
      test: ['CMD-SHELL', "ps aux | grep '[s]idekiq\ 6' || false"]
    volumes:
      - 'mastodon-volume:/mastodon/public/system'
    env_file:
      - ./envs/mastodon.env
    depends_on:
      - postgresdb
      - redis
    networks:
      - internal_network
      - external_network

  mastodon-streaming:
    container_name: mastodon-streaming
    image: 'ghcr.io/mastodon/mastodon-streaming:latest'
    restart: always
    command: node ./streaming/index.js
    healthcheck:
      test: ['CMD-SHELL', "curl -s --noproxy localhost localhost:4000/api/v1/streaming/health | grep -q 'OK' || exit 1"]
    ports:
      - '127.0.0.1:4000:4000'
    env_file:
      - ./envs/mastodon.env
    depends_on:
      - postgresdb
      - redis
    networks:
      - external_network
      - internal_network

networks:
  external_network:
  internal_network:
    internal: true

volumes:
  redis:
  postgres-db:
  mastodon-volume:

File redis.env for the Redis database:

REDIS_PASSWORD=""

File postgres.env for the Postgres database:

POSTGRES_PASSWORD=""

File mastodon.env:

RAILS_ENV="production"
LOCAL_DOMAIN="social.alexn.org"
# WEB_DOMAIN="social.alexn.org"

# Must create DB user and database
DB_HOST="postgresdb"
DB_NAME="mastodon"
DB_USER="mastodon"
DB_PASS=

# Must reuse the password from `redis.env`
REDIS_URL="redis://default:password@redis:6379"

# -----------
# App Secrets
# -----------
# Can be generated with:
# docker-compose run --rm mastodon-web bundle exec rake secret
# -----------
SECRET_KEY_BASE=
OTP_SECRET=

# -----------
# Secrets for DB encryption
# -----------
# Can be generated with:
# docker run -it ghcr.io/mastodon/mastodon:latest bin/rails db:encryption:init
# -----------
ACTIVE_RECORD_ENCRYPTION_DETERMINISTIC_KEY=
ACTIVE_RECORD_ENCRYPTION_KEY_DERIVATION_SALT=
ACTIVE_RECORD_ENCRYPTION_PRIMARY_KEY=

# ----------------------
# Web Push Notifications
# ----------------------
# Generate with `rake mastodon:webpush:generate_vapid_key`
#
# docker exec mastodon-web bundle exec rake mastodon:webpush:generate_vapid_key
# ----------------------
VAPID_PRIVATE_KEY=
VAPID_PUBLIC_KEY=

# --------
MASTODON_ADMIN_USERNAME="alexelcu"
MASTODON_ADMIN_EMAIL="alexelcu@social.alexn.org"

# ------------------------------------------
# Email settings / via external SMTP service
# ------------------------------------------
# See Fastmail's App Passwords:
# https://www.fastmail.help/hc/en-us/articles/360058752854-App-passwords
# ------------------------------------------
SMTP_SERVER="smtp.fastmail.com"
SMTP_PORT=465
SMTP_FROM_ADDRESS="noreply@social.alexn.org"
SMTP_LOGIN=
SMTP_PASSWORD=

# --------------------------------
# For enabling cloud block storage
# --------------------------------
# S3_ENABLED=true
# S3_PROTOCOL=https
# S3_ENDPOINT=https://s3.eu-central-003.backblazeb2.com
# S3_HOSTNAME=s3.eu-central-003.backblazeb2.com
# S3_BUCKET=alexn-social-files
# AWS_ACCESS_KEY_ID=
# AWS_SECRET_ACCESS_KEY=
# S3_ALIAS_HOST="files-social.alexn.org"

Postgres Setup

To create the database for Mastodon, first connect via the psql client:

docker exec -it postgresdb psql -U postgres

Then run:

CREATE DATABASE mastodon;
CREATE USER mastodon WITH ENCRYPTED PASSWORD 'your-password';
GRANT ALL PRIVILEGES ON DATABASE mastodon TO mastodon;
-- Above was apparently not enough to run DB migrations,
-- so this is needed too:
ALTER DATABASE mastodon OWNER TO mastodon;

Nginx Config

Mastodon has an official recommended Nginx configuration (see their repository), however I am hosting Mastodon inside a Docker container, and using Cloudflare, which makes things more complicated.

Make sure to check your HTTP caching headers (Cache-Control), and ensure it plays well with Cloudflare 😉

Here’s my /etc/nginx/available-sites/social.alexn.org.conf file:

upstream backend {
    server 127.0.0.1:3000 fail_timeout=0;
}

upstream streaming {
    server 127.0.0.1:4000 fail_timeout=0;
}

server {
    server_name social.alexn.org;
    listen   80;
    listen   [::]:80;

    access_log /var/log/nginx/social.alexn.org.log combined;

    location ~ /.well-known {
        root   /var/www/social.alexn.org;
        allow all;
        break;
    }

    location / {
        rewrite ^(.*)$ https://social.alexn.org$1 permanent;
    }
}

server {
    server_name social.alexn.org;
    listen 443 ssl;
    listen [::]:443 ssl;

    access_log /var/log/nginx/social.alexn.org.log combined;

    ###############
    # SSL

    # certs sent to the client in SERVER HELLO are concatenated in ssl_certificate
    ssl_certificate /etc/letsencrypt/live/alexn.org/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/alexn.org/privkey.pem;

    ## verify chain of trust of OCSP response using Root CA and Intermediate certs
    ssl_trusted_certificate /etc/letsencrypt/live/alexn.org/fullchain.pem;

    # Common config
    include ./snippets/ssl.conf;

    # END SSL
    ##############

    keepalive_timeout    70;
    sendfile             on;
    client_max_body_size 80m;

    root /var/www/social.alexn.org;
    include ./snippets/gzip.conf;

    location / {
        proxy_pass http://backend;
        include ./snippets/proxy-backend.conf;
    }

    location = /sw.js {
        proxy_pass http://backend;
        add_header Cache-Control "public, max-age=604800, must-revalidate";
        include ./snippets/proxy-backend.conf;
    }

    location ~ ^/system/ {
        proxy_pass http://backend;
        add_header Cache-Control "public, max-age=2419200, immutable";
        include ./snippets/proxy-backend.conf;
    }

    location ~ ^/(assets/|avatars/|emoji/|headers/|packs/|shortcuts/|sounds/) {
        proxy_pass http://backend;
        add_header Cache-Control "public, max-age=2419200, must-revalidate";
        include ./snippets/proxy-backend.conf;
    }

    location ^~ /api/v1/streaming {
        proxy_pass http://streaming;
        include ./snippets/proxy-streaming.conf;
    }

    error_page 500 501 502 503 504 /500.html;
}

Depends on this ./snippets/ssl.conf:

###
# https://ssl-config.mozilla.org/#server=nginx&version=1.17.7&config=intermediate&openssl=1.1.1k&guideline=5.6

ssl_session_timeout 1d;
ssl_session_cache shared:SSL:10m;  # about 40000 sessions
ssl_session_tickets off;

# Diffie-Hellman parameter for DHE ciphersuites, recommended 2048 bits
ssl_dhparam /etc/nginx/certs/dh2048.pem;

# intermediate configuration
ssl_protocols TLSv1.2 TLSv1.3;
ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
ssl_prefer_server_ciphers off;

# HSTS (ngx_http_headers_module is required) (63072000 seconds)
add_header Strict-Transport-Security "max-age=63072000; includeSubdomains; preload";

# OCSP stapling
ssl_stapling on;
ssl_stapling_verify on;

Also, depends on ./snippets/proxy-backend.conf:

include ./snippets/cloudflare-ips.conf;

proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header Proxy "";
proxy_pass_header Server;

proxy_buffering on;
proxy_redirect off;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;

proxy_cache CACHE;
proxy_cache_valid 200 7d;
proxy_cache_valid 410 24h;
proxy_cache_use_stale error timeout updating http_500 http_502 http_503 http_504;

add_header X-Cached $upstream_cache_status;
tcp_nodelay on;

Also, depends on ./snippets/proxy-streaming.conf:

include ./snippets/cloudflare-ips.conf;

proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header Proxy "";

proxy_buffering off;
proxy_redirect off;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;

Also, depends on ./snippets/cloudflare-ips.conf:

## Docs:
# https://support.cloudflare.com/hc/en-us/articles/200170786-Restoring-original-visitor-IPs-Logging-visitor-IP-addresses-with-mod-cloudflare-
#
# MUST KEEP UP TO DATE!

# https://www.cloudflare.com/ips-v4
set_real_ip_from 173.245.48.0/20;
set_real_ip_from 103.21.244.0/22;
set_real_ip_from 103.22.200.0/22;
set_real_ip_from 103.31.4.0/22;
set_real_ip_from 141.101.64.0/18;
set_real_ip_from 108.162.192.0/18;
set_real_ip_from 190.93.240.0/20;
set_real_ip_from 188.114.96.0/20;
set_real_ip_from 197.234.240.0/22;
set_real_ip_from 198.41.128.0/17;
set_real_ip_from 162.158.0.0/15;
set_real_ip_from 104.16.0.0/13;
set_real_ip_from 104.24.0.0/14;
set_real_ip_from 172.64.0.0/13;
set_real_ip_from 131.0.72.0/22;

# https://www.cloudflare.com/ips-v6
set_real_ip_from 2400:cb00::/32;
set_real_ip_from 2606:4700::/32;
set_real_ip_from 2803:f800::/32;
set_real_ip_from 2405:b500::/32;
set_real_ip_from 2405:8100::/32;
set_real_ip_from 2a06:98c0::/29;
set_real_ip_from 2c0f:f248::/32;

real_ip_header CF-Connecting-IP;

Also, depends on this ./snippets/gzip.conf:

gzip on;
gzip_disable "msie6";

# Enable compression both for HTTP/1.0 and HTTP/1.1.
gzip_http_version  1.1;

# Compression level (1-9).
# 5 is a perfect compromise between size and cpu usage, offering about
# 75% reduction for most ascii files (almost identical to level 9).
gzip_comp_level    6;

# Don't compress anything that's already small and unlikely to shrink much
# if at all (the default is 20 bytes, which is bad as that usually leads to
# larger files after gzipping).
gzip_min_length    256;

# Compress data even for clients that are connecting to us via proxies,
# identified by the "Via" header (required for CloudFront).
gzip_proxied       any;

# Tell proxies to cache both the gzipped and regular version of a resource
# whenever the client's Accept-Encoding capabilities header varies;
# Avoids the issue where a non-gzip capable client (which is extremely rare
# today) would display gibberish if their proxy gave them the gzipped version.
gzip_vary          on;

# Sets the number and size of buffers used to compress a response.
# By default, the buffer size is equal to one memory page.
# This is either 4K or 8K, depending on a platform.
gzip_buffers	16 8k;

# Compress all output labeled with one of the following MIME-types.
gzip_types
	application/atom+xml
	application/font-woff
	application/javascript
	application/json
	application/rss+xml
	application/vnd.ms-fontobject
	application/x-font-ttf
	application/x-font-woff
	application/x-web-app-manifest+json
	application/xhtml+xml
	application/xml
	application/xml+rss
	font/opentype
	font/woff
	font/woff2
	image/svg+xml
	image/x-icon
	text/css
	text/javascript
	text/plain
	text/x-component
	text/xml;

Backups

Script for periodically backing up Postgres via rclone, to install in cron.d:

#!/usr/bin/env bash

set -e

FILENAME="postgres-$(date +"%Y-%m").sql.gz"
FILEPATH="/var/lib/my-backups/$FILENAME"

mkdir -p /var/lib/my-backups

docker exec -i postgresdb pg_dumpall -U postgres | gzip > "$FILEPATH"

if [ -f "$FILEPATH" ]; then
  rclone copy "$FILEPATH" "backup:Postgres/"
fi

rm -f /var/lib/my-backups/postgres-*.sql.gz

Script for periodically backing up your media files (but without the cache), via rclone, to install in cron.d:

#!/usr/bin/env bash

set -e

FILENAME="mastodon-volume.tar"
FILEPATH="/var/lib/my-backups/$FILENAME"

docker run \
    --rm \
    --volumes-from mastodon-web \
    -v /var/lib/my-backups:/backup \
    ubuntu \
    tar --exclude='mastodon/public/system/cache' -cf "/backup/$FILENAME" -C / "mastodon/public/system" \
    2>&1

if [ -f "$FILEPATH" ]; then
  rclone copy "$FILEPATH" "backup:Mastodon/"
  rm -f "$FILEPATH"
fi

There may be better ways of doing this (like simply using block storage), I’m still learning.

Java

Alexandru Nedelcu — Mon, 12 Sep 2022 05:58:10 +0000

Article updated at April 4, 2025, created at September 12, 2022.

Resources

Core functionality

Guava;
Vavr: persistent collections, Scala-inspired;
PCollections: persistent collections;

SQL libraries

Hibernate: ORM, and I hate ORMs;
JDBI: light layer on top of JDBC, string-based queries;
jOOQ: type safe SQL, alternative to Hibernate;

Database migrations

Flyway;
Liquidbase;

Frameworks

Dropwizard;
Quarkus: built for compatibility with GraalVM’s native image;
Spring Boot (see the initializer);

Tools

Gradle: the accepted Maven alternative;
JBang: scripting with Java;

Setup

SDKMan!

Install:

https://sdkman.io/install

To list available Java SDKs:

sdk list java

To install:

# OpenJDK
sdk install java 11.0.2-open

# GraalVM
sdk install 22.2.r17-grl

# Oracle
sdk install 17.0.4-oracle

After the installation of GraalVM, add this to .zshrc:

export GRAALVM_HOME=$HOME/.sdkman/candidates/java/22.2.r17-grl/

Also install the native-image:

${GRAALVM_HOME}/bin/gu install native-image

OpenJDK Builds

Noteworthy:

Eclipse Temurin: the old AdoptOpenJDK;
IBM Semeru: these are the new OpenJ9 builds;
jdk.java.net: reference OpenJDK builds;

Also see: JDK distributions.

Resources / Links

New Developer Friendly Features After Java 8 — Piotr Mińkowski;
New language features since Java 8 to 18 — Dávid Csákvári;

Dependency injection / CDI

Quarkus / CDI and “java config” DI definitions;
- Composition Root;

GC / Garbage Collection tweaks

Since Java 24+:

-XX:+UnlockExperimentalVMOptions -XX:+UseCompactObjectHeaders

Chromium (Brave, Vivaldi, …)

Alexandru Nedelcu — Thu, 01 Sep 2022 13:10:16 +0000

Article updated at February 4, 2023, created at September 1, 2022.

Favorite Extensions

1Password;
ChatGPT for Google (GitHub): displays ChatGPT response alongside search results, works with all search engines, not just Google;
Consent-o-matic (GitHub): automatic handling of GDPR consent popups;
Dark Reader;
Enhancer for YouTube;
LanguageTool: for spell-checking, can run with a local server (brew install languagetool);
LeechBlock NG: Time-based restrictions for websites;
Netflix 1080p (GitHub): enables 1080p on Netflix;
Old Reddit Redirect (GitHub): redirects all Reddit links to old.reddit.com;
Picture-in-Picture Extension (by Google) (make sure to disable Google Analytics);
Save to Pocket;
Tab pinner (GitHub): adds a keyboard shortcut for pinning/unpinning a tab;
Tabliss (GitHub): a customizable new tab page with beautiful backgrounds;
uBlock Origin, the best ad-blocker, deprecated due to MV3;
Vimium (GitHub): adds some Vim-like keyboard shortcuts;

Ad-blocking compatible with Manifest v3:

AdGuard AdBlocker MV3 Experimental: an experimental ad-blocker, built on top of Manifest v3;
uBlock Origin Lite: a version of uBlock Origin based on Manifest V3;

Internal URLs

about://chrome-urls: lists all special URLs;
about://flags: for activating experimental browser features;

Brave-specific:

brave://adblock: for adding extra filter lists to Brave;
brave://rewards-internals: for debugging Brave’s Rewards;

Chrome alternatives

Misc

Ubuntu Server

Alexandru Nedelcu — Fri, 11 Mar 2022 11:59:24 +0000

Article updated at September 1, 2022, created at March 11, 2022.

Initial setup (firewall, user, updates)

As root:

# Installing available security updates
apt update && apt upgrade

# Enabling firewall (super important!)
apt install ufw
ufw default deny incoming
# I've decided to be super strict and block everything by default

# SSH
ufw allow in 22
# HTTP(S)
ufw allow in 80
ufw allow in 443

We can also configure the firewall to deny outgoing connections:

ufw default deny outgoing
# SSH
ufw allow out 22
# HTTP(S)
ufw allow out 80
ufw allow out 443

# Allow DNS requests
ufw allow out 53

# Allow outgoing SMTP via FastMail
ufw allow out 587

Enable ufw (after making sure that SSH is enabled):

ufw --force enable

Status should now look like this:

root@vm~# ufw status
Status: active

To                         Action      From
--                         ------      ----
OpenSSH                    ALLOW       Anywhere
80                         ALLOW       Anywhere
443                        ALLOW       Anywhere
OpenSSH (v6)               ALLOW       Anywhere (v6)
80 (v6)                    ALLOW       Anywhere (v6)
443 (v6)                   ALLOW       Anywhere (v6)

80                         ALLOW OUT   Anywhere
443                        ALLOW OUT   Anywhere
53                         ALLOW OUT   Anywhere
587                        ALLOW OUT   Anywhere
80 (v6)                    ALLOW OUT   Anywhere (v6)
443 (v6)                   ALLOW OUT   Anywhere (v6)
53 (v6)                    ALLOW OUT   Anywhere (v6)
587 (v6)                   ALLOW OUT   Anywhere (v6)

Fix the UFW+Docker combination via ufw-docker utility (otherwise Docker will just ignore your firewall rules):

wget -O /usr/local/bin/ufw-docker \
  https://github.com/chaifeng/ufw-docker/raw/master/ufw-docker

chmod +x /usr/local/bin/ufw-docker

ufw-docker install

systemctl restart ufw

Creating a new user and disabling root:

adduser alex
# Adds the user to sudoers
usermod -aG sudo alex

# Create its OpenSSH config
mkdir /home/alex/.ssh
vim /home/alex/.ssh/authorized_keys
chmod -R go-rwx /home/alex/.ssh
chown -R alex:alex /home/alex/.ssh

# Disable root's password
passwd -l root

# It's a good time to reboot
reboot

Setup automatic updates:

sudo apt-get install unattended-upgrades
sudo dpkg-reconfigure -plow unattended-upgrades

Edit /etc/apt/apt.conf.d/50unattended-upgrades for customizations.

Secure OpenSSH

Edit the config file:

sudo vim /etc/ssh/sshd_config

Add these options:

Port 22
Protocol 2
LoginGraceTime 30
PermitRootLogin no
AllowUsers alex
StrictModes yes
MaxAuthTries 3
IgnoreRhosts yes
PasswordAuthentication no
PermitEmptyPasswords no
ChallengeResponseAuthentication no
KerberosAuthentication no
GSSAPIAuthentication no
UsePAM no
AllowAgentForwarding no
AllowTcpForwarding no
X11Forwarding no
PrintMotd yes
ClientAliveInterval 6m
ClientAliveCountMax 0
UseDNS no
PermitTunnel no

Configure sending emails via FastMail (or another SMTP server)

sudo apt-get install postfix mailutils libsasl2-2 ca-certificates libsasl2-modules

Add the following lines in /etc/postfix/main.cf:

relayhost = [smtp.fastmail.com]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_CAfile = /etc/postfix/cacert.pem
smtp_use_tls = yes

Create /etc/postfix/sasl_passwd:

[smtp.fastmail.com]:587 username:password

Fix the permissions:

sudo chmod 400 /etc/postfix/sasl_passwd

Tell postfix about the password entry:

sudo postmap /etc/postfix/sasl_passwd

Download the Thawte Primary Root CA if not available:

cd /etc/ssl/certs/
sudo wget https://www.thawte.com/roots/thawte_Primary_Root_CA.pem

Then create cacert.pem:

sudo cp /etc/ssl/certs/thawte_Primary_Root_CA.pem /etc/postfix/cacert.pem

Restart the service:

sudo /etc/init.d/postfix reload

Test it:

echo "Test Email message body" | mail -s "Email test subject"  test@domain.tld

Install ClamAV anti-virus

sudo apt install clamav -y

Update its definitions:

sudo systemctl stop clamav-freshclam

sudo freshclam

sudo systemctl start clamav-freshclam

Install swap file

Source: https://bookofzeus.com/harden-ubuntu/server-setup/add-swap/

# Let's check if a SWAP file exists and it's enabled before we create one.
sudo swapon -s

# To create the SWAP file, you will need to use this.
sudo fallocate -l 4G /swapfile

# Secure swap.
sudo chown root:root /swapfile
sudo chmod 0600 /swapfile

# Prepare the swap file by creating a Linux swap area.
sudo mkswap /swapfile

# Activate the swap file.
sudo swapon /swapfile

# Confirm that the swap partition exists.
sudo swapon -s

# This will last until the server reboots. Let's create the entry in the fstab.
sudo nano /etc/fstab
: /swapfile	none	swap	sw	0 0

# Swappiness in the file should be set to 0. Skipping this step may cause both poor performance,
# whereas setting it to 0 will cause swap to act as an emergency buffer, preventing out-of-memory crashes.
echo 0 | sudo tee /proc/sys/vm/swappiness
echo vm.swappiness = 0 | sudo tee -a /etc/sysctl.conf

Excel

Alexandru Nedelcu — Sat, 29 Jan 2022 16:21:03 +0000

Article updated at September 1, 2022, created at January 29, 2022.

Shortcuts:

Ctrl-D/Cmd-D: fill the selected cell with the content of the cell above;
Ctrl-G: “go to” any area;
Ctrl-K/Cmd-K: insert hyperlink;
Ctrl-L: define name for cell range;
Ctrl-R/Cmd-R: fill the selected cell with the content of the cell on the left;
Ctrl-;: enter the current date in a cell;
Cmd-;: enter the current time in a cell;

Unix shell (CLI)

Alexandru Nedelcu — Sat, 29 Jan 2022 05:08:17 +0000

Article updated at May 15, 2023, created at January 29, 2022.

Find zombie processes:

ps axo stat,ppid,pid,comm | grep -w defunct

Measure memory

Useful project: https://github.com/astrofrog/psrecord

psrecord \
    --duration 30 \
    --interval 2 \
    --include-children \
    --plot /tmp/plot.png \

Load/unload environment variables based on directory

https://github.com/direnv/direnv

brew install direnv

For integrating with zsh, add in ~/.zshrc:

eval "$(direnv hook zsh)"

TLS/SSL (HTTPS)

Alexandru Nedelcu — Thu, 24 Jun 2021 07:13:23 +0000

Article updated at September 1, 2022, created at June 24, 2021.

Download the certificate of a domain:

echo -n | openssl s_client -connect google.com:443 -servername google.com | openssl x509

Verify that the certificate corresponds to CA certificate:

openssl verify -verbose -purpose sslserver -CAfile /path/to/cafile.pem /path/to/cert.pem

Web

Alexandru Nedelcu — Mon, 30 Nov 2020 14:38:13 +0000

Article updated at August 31, 2025, created at November 30, 2020.

Browser benchmarks

Performance:

Features:

For testing tracking & ads blocking

Block lists

Extra lists I used:

Hide YouTube Shorts
Huge AI Blocklist
Bypass Paywalls Clean filters (unsure if this is trustworthy)

Personal:

Progressive Web Apps (PWAs)

Wrap web pages as desktop apps

Using: https://github.com/jiahaog/nativefier

nativefier \
    --maximize \
    -u "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:76.0) Gecko/20100101 Firefox/76.0" \
    --internal-urls ".*.google.com.*" \
    --name "YouTube Music" \
    "https://music.youtube.com/"

nativefier \
    -u "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:76.0) Gecko/20100101 Firefox/76.0" \
    --maximize \
    --counter \
    --name "Twitter" \
    "https://x.com"

nativefier \
    -u "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:76.0) Gecko/20100101 Firefox/76.0" \
    --maximize \
    --counter \
    --name "Gitter" \
    "https://gitter.im"

Browser comparisons

Client Tricks

Detect the Brave Browser

(navigator.brave && await navigator.brave.isBrave() || false)

Credit: https://stackoverflow.com/a/60954062

Detect Dark Mode

From JavaScript:

"matchMedia" in window &&
window.matchMedia('(prefers-color-scheme: dark)').matches

From CSS:

@media (prefers-color-scheme: dark) {
    /* ... */
}

Detect Dark Reader (browser extension)

For detecting the Dark Reader browser extension:

"querySelector" in document &&
!!document.querySelector("meta[name=darkreader]")

Vim

Alexandru Nedelcu — Wed, 04 Nov 2020 11:57:32 +0000

Article updated at September 1, 2022, created at November 4, 2020.

Docs & Articles

Important:

Vim Cheatsheet (archive) / Github Repo (archive)
Vim Graphical Cheatsheet (archive)

Other:

Setup

Installing the Python provider

Some plugins require the Python provider to be available. This can be checked with the following vim command:

:checkhealth provider

This requires the pynvim Python package. It’s best if the setup uses virtualenv. On macOS prefer to use pyenv:

brew install pyenv pyenv-virtualenv

This needs the following initialization code in ~/.zshrc:

eval "$(pyenv init -)"
eval "$(pyenv virtualenv-init -)"

Then, install a Python 3 version:

pyenv install 3.10.6

Create a new virtualenv:

pyenv virtualenv 3.10.6 neovim

Activate it temporarily in your shell session:

pyenv activate neovim

Install the required Python package:

pip install pynvim

Then add this to ~/.config/nvim/init.vim:

let g:python3_host_prog=expand('~/.pyenv/versions/neovim/bin/python')

Random tips

Documentation

:help
:help g
:help motion.txt
:help spell.txt
:help user-manual
:help visual.txt

Surround text

Functionality from vim-surround, which also works in VS Code (with VSCodeVim):

v                    # Enter visual mode
    # Use the keyboard to select the section of text
s                    # Press upper case S
"                    # Specify what you want to surround the visual selection with

Visual-block mode

This works like (and implemented with) multi-cursors in other editors (see VS Code (archive)).

Ctrl-v to enter visual-block mode
- Select block
I (capital letter) to enter insert mode
to exit insert mode

Copy & Paste

Shortcuts:

d is for cut, y is for copy, p or P are for paste

Normally one uses the clipboard register to cut, copy and paste, which is *. So "*y copies to the system clipboard, and "*p pastes from that clipboard.

To activate the system clipboard for copy and pasting with the “unnamed” register, add this to .vimrc:

set clipboard+=unnamed

Fold / Unfold

zc: fold
zo: unfold
zM: fold all
zR: unfold all

Go to …

gd: go to definition
gx: open link
Ctrl+O: jump back to last position

Vimdiff

do: Get changes from other window into the current window
dp: Put the changes from current window into the other window.
]c: Jump to the next change.
[c: Jump to the previous change.
Ctrl W + Ctrl W: Switch to the other split window.

Record macros

to record macros: qq
- pressing qa starts recording in register a
- pressing q again stops recording
to view recorded macros: :reg
to play the macro once: @
- @a plays the macro in register a
to repeat the macro execution: @@

LazyVim setup

The following tips assume LazyVim.

Shortcuts

Search for files:

Search text in files:

sg

View list of errors and warnings reported in project:

xx

Switch to window:

Ctrl-w + h/j/k/l

Close current window:

Ctrl-w + q

Open link at cursor:

gx

Go to definition at cursor:

gd

Go back:

Ctrl-t

Android

Alexandru Nedelcu — Mon, 02 Nov 2020 19:09:46 +0000

Article updated at September 1, 2022, created at November 2, 2020.

Apps

DAVx5: CalDAV/CardDAV for Android
F-Droid: FOSS app store
FeedMe RSS Reader
Firefox for Android
Foxit PDF Reader
LibreTorrent: open-source torrent client
Moon+ Reader Pro: e-book reader
Newsblur: RSS reader service
Orgzly: notes and to-do lists, Org-Mode
OsmAnd: maps based on OpenStreetMap and Wikipedia
Pocket Casts: podcasts
Resilio Sync: local files sync
Talon (store): open-source Twitter client
Tasker: automation
Termux: terminal emulator and Linux environment
VLC: video player
Voice: open-source audiobook player

Deskreen: for sharing the desktop’s screen over the local network, works with any device
Scrcpy: display & control Android device from desktop

Microsoft .NET (dotNET)

Alexandru Nedelcu — Thu, 08 Oct 2020 05:31:40 +0000

Article updated at December 23, 2023, created at October 8, 2020.

.NET Core

To build self-contained executables, add this in .csproj/.fsproj:


    true
    true
    true

For NativeAOT:

zerosharp: “demo of the potential of C# for systems programming with the .NET native ahead-of-time compilation technology”;

Libraries (General)

Database migrations:

DbUp;
Fluent Migrator.

C# (CSharp)

Game Development

Game Development with .NET (article)
Available game engines

Web Development

# Starting a new solution
dotnet new sln -o MyBigProject
cd MyBigProject

# Start a new web app
dotnet new webapp -o web-app --no-https -f net7.0
cd web-app

# Start development server
dotnet watch

F# (FSharp)

Start New Project

# Starting a new solution
dotnet new sln -o AdventOfCode

# Start a console applicatin
cd AdventOfCode/
dotnet new console -lang "F#" -o App

# Add project to the solution
dotnet sln add App/App.fsproj

# Restore NuGet dependencies
dotnet restore

# Build the project
dotnet build

# Run the project
cd ./App
dotnet run

# Build for release
dotnet publish --configuration Release

Articles

Native AOT:

Presentations

Don Syme - Keynote - F# Code I Love

Templates

ProjectScaffold: template for new projects
MiniScaffold

Tools (F#)

Forge: for creating projects
Paket: for Nuget dependencies management
FAKE: build management

Libraries (F#)

Unit testing:

Expecto.

Database access:

EFCore Sharp: F# migrations (design-time) support for EF Core.

Privacy

Alexandru Nedelcu — Mon, 21 Sep 2020 13:20:35 +0000

Article updated at September 1, 2022, created at September 21, 2020.

Firefox Extensions

Safari Extensions

Wipr (iOS, macOS)

Network-wide blocking

Pi-hole
NextDNS (pi-hole as a service)
StevenBlack/hosts for blocking via /etc/hosts

Testing

VPN

De-DRM

Alexandru Nedelcu — Thu, 17 Sep 2020 09:02:43 +0000

Article updated at September 1, 2022, created at September 17, 2020.

e-Books

Tools:

Installation for Calibre:

brew cask install calibre

For DeDRM:

Using the DeDRM plugin with the Calibre command line interface

Audible Audiobooks

Extract encryption keys: https://github.com/inAudible-NG/audible-activator

Then:

ffmpeg -activation_bytes XXXXXXXX -i in.AAX out.mp3

Or for m4b, without transcoding, keeping all metadata:

ffmpeg -activation_bytes XXXXXXXX -i in.AAX -c copy out.m4b

Image Formats

Alexandru Nedelcu — Tue, 15 Sep 2020 18:48:09 +0000

Article updated at September 1, 2022, created at September 15, 2020.

Convert HEIC to JPEG in a directory

#!/usr/bin/env bash

set -e
shopt -s nocaseglob

echo "Converting directory: $1"
cd "$1" || exit 1

convert()
{
    local source="$1"
    local dest="${source//.HEIC/.jpeg}"
    dest="${dest//.heic/.jpeg}"
    sips -s format jpeg "$source" --out "$dest"
}

find . -iname "*.heic" | while read file; do convert "$file"; done

Converting to AVIF/WebP/Other

Use: squoosh/cli

Apache Kafka

Alexandru Nedelcu — Fri, 04 Sep 2020 07:30:08 +0000

Article updated at April 8, 2023, created at September 4, 2020.

Docker Setup

  #
  # Kafka config taken from:
  # https://raw.githubusercontent.com/bitnami/bitnami-docker-kafka/master/docker-compose.yml
  #

  zookeeper:
    image: bitnami/zookeeper:latest
    container_name: zookeeper
    networks: [ main ]
    ports:
      - '2181:2181'
    volumes:
      - 'zookeeper_data:/bitnami'
    environment:
      - ALLOW_ANONYMOUS_LOGIN=yes

  kafka:
    image: bitnami/kafka:latest
    container_name: kafka
    networks: [ main ]
    ports:
      - '9092:9092'
    volumes:
      - 'kafka_data:/bitnami'
    environment:
      # - KAFKA_BROKER_ID=1
      - KAFKA_LISTENERS=PLAINTEXT://:9092
      - KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://127.0.0.1:9092
      - KAFKA_ZOOKEEPER_CONNECT=zookeeper:2181
      - ALLOW_PLAINTEXT_LISTENER=yes
    depends_on:
      - zookeeper

Utils

To create topics:

docker exec -it kafka /opt/bitnami/kafka/bin/kafka-topics.sh \
    --create \
    --zookeeper zookeeper:2181 \
    --replication-factor 1 \
    --partitions 1 \
    --topic test

To view messages pushed to a topic:

docker exec -it kafka /opt/bitnami/kafka/bin/kafka-console-consumer.sh \
  --bootstrap-server localhost:9092 \
  --from-beginning \
  --topic test

To push messages on a topic:

docker exec -it kafka /opt/bitnami/kafka/bin/kafka-console-producer.sh \
    --broker-list localhost:9092 \
    --topic test

Tools:

provectus/kafka-ui: Open-Source Web UI for Apache Kafka Management;

Agile

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Kanban

Eric Brechner: “Agile Project Management with Kanban”

Notes:

WIP - limit number of tickets equal to number of people, with some buffer
Unlimited in scope as far as time goes
Tasks should be limited to be smaller in size
Example board:
- Backlog
- Breakdown
- Implement
- Validate
Each column has an “in progress” and “done” sub-columns

Cloudflare

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Invalidate cache

Create an API token:

go here: https://dash.cloudflare.com/profile/api-tokens
select permissions: Zone.Zone (Read) and Zone.Cache Purge (Purge)

Screenshot of how that looks like:

Bash function:

#!/usr/bin/env bash

cloudflare_invalidate_cache() {
  local DOMAIN_NAME="$1"
  local CF_API_TOKEN="$2"

  if [[ -z "$DOMAIN_NAME" ]]; then
    echo >&2 "ERROR (invalidating cloudflare): DOMAIN_NAME (1) not given!"
    exit 1
  fi

  if [[ -z "$CF_API_TOKEN" ]]; then
    echo >&2 "ERROR (invalidating cloudflare): CF_API_TOKEN (2) is not set!"
    exit 1
  fi

  echo "--- Purging Cloudflare cache for $DOMAIN_NAME"
  
  CF_ZONEID=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones" -H "Authorization: Bearer $CF_API_TOKEN" -H "Content-Type: application/json" | jq -r '.result[] | "\(.id) \(.name)"' | grep "$DOMAIN_NAME" | cut -f1 -d" ")
  curl -s -X POST "https://api.cloudflare.com/client/v4/zones/$CF_ZONEID/purge_cache" -H "Authorization: Bearer $CF_API_TOKEN" -H "Content-Type: application/json" --data '{"purge_everything":true}' 1>/dev/null
  return 0
}

Required tools for this work:

jq
curl, grep

Debian Packages (deb)

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

DNS settings

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

MacOS

Refresh DNS

To flush the local DNS cache:

sudo dscacheutil -flushcache
sudo killall -HUP mDNSResponder

Set DNS to Cloudflare

To set the DNS to Cloudflare’s 1.1.1.1:

sudo networksetup -setdnsservers Wi-Fi 1.1.1.1 1.0.0.1 2606:4700:4700::1111 2606:4700:4700::1001

sudo networksetup -setdnsservers "USB 10/100/1000 LAN" 1.1.1.1 1.0.0.1 2606:4700:4700::1111 2606:4700:4700::1001

To revert the setup:

sudo networksetup -setdnsservers "Wi-Fi" empty

sudo networksetup -setdnsservers "USB 10/100/1000 LAN" empty

To see what DNS service the connection is using:

$ nslookup google.com
Server:		1.1.1.1
Address:	1.1.1.1#53

Non-authoritative answer:
Name:	google.com
Address: 172.217.21.238

Split DNS

Source: https://gist.github.com/dferg/0472269333be4aca6aaa21cf3b165c02

Sometimes you may want to use a DNS server for specific domain requests and another DNS server for all other requests. This is helpful, for instance, when connected to a VPN. For hosts behind that VPN you want to use the VPN’s DNS server but all other hosts you want to use Google’s public DNS. This is called “DNS splitting.”

Here, we run dnsmasq as a background service on macOS. The dnsmasq configuration described below implements DNS splitting.

Install via Homebrew:

brew install dnsmasq

Edit $(brew --prefix)/etc/dnsmasq.conf:

# Ignore /etc/resolv.conf
no-resolv

# For queries *.domain.com and *.domain.net, forward to the specified DNS server
# Servers are queried in order (if the previous fails)
# -- Note: These are EXAMPLES. Replace with your desired config.
server=/domain.com/domain.net/IP_ADDR_OF_SERVER1
server=/domain.com/domain.net/IP_ADDR_OF_SERVER2

# Forward all other requests to Google's public DNS server
server=8.8.8.8

# Only listen for DNS queries on localhost
listen-address=127.0.0.1

# Required due to macOS limitations
bind-interfaces

Start the service:

sudo brew services start dnsmasq

Point to the new local DNS server:

sudo networksetup -setdnsservers "Wi-Fi" 127.0.0.1

sudo networksetup -setdnsservers "USB 10/100/1000 LAN" 127.0.0.1

Uninstall dnsmasq

sudo brew services stop dnsmasq
brew uninstall dnsmasq
rm "$(brew --prefix)/etc/dnsmasq.conf"
sudo networksetup -setdnsservers "Wi-Fi" empty

NextDNS

Install:

brew install nextdns/tap/nextdns

sudo nextdns install \
  -report-client-info \
  -auto-activate \
  -detect-captive-portals \
  --config

Docker

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Installation

MacOS

brew cask install docker

Basic usage

Running a container interactively

Pulling an existing from the repository:

docker pull nats:latest

Then to run this image in a container:

docker run -p 4222:4222 -ti nats:latest

Params used:

-p: publishes a container’s port (a mapping from container to host)
-i: keep STDIN open even if not attached — this means | docker run works
-t: allocates a pseudo-TTY, which in combination with -i means we can interact with the process

Running a container as daemon

For this we add the -d option:

docker run -p 4222:4222 -d -ti nats:latest

List containers

List active containers:

docker ps --no-trunc

List all containers:

docker ps -a

Start & stop containers

Stops container with the id :

docker stop

Stops all running containers:

docker stop $(docker ps -a -q)

To re-start a certain container:

docker start

Remove containers

docker rm

Remove all containers:

docker rm $(docker ps -a -q)

If some containers are still running as a daemon, use -f (force):

docker rm -f $(docker ps -a -q)

Remove orphan volumes

List:

docker volume ls -qf dangling=true

Remove:

docker volume rm $(docker volume ls -qf dangling=true)

List or remove images

List images available locally:

docker images

Remove all images:

docker rmi $(docker images -q -a)

List or remove volumes

docker volume ls

To remove:

docker volume rm

Remove all volumes:

docker volume rm $(docker volume ls -q)

Gain shell access to a container

docker exec -it  sh

Clean Restart of all Docker Instances

# Stop all containers
docker-compose down

# Delete all containers
docker rm -f $(docker ps -a -q)

# Delete all volumes
docker volume rm $(docker volume ls -q)

# Restart all containers
docker-compose up -d

Building Docker images

Resources:

Dockerizing a Node.js web app

Auto-update containers to latest

Run watchtower container, with option to auto update only labelled containers:

docker run -d \
  --restart=always \
  --name=watchtower \
  -v /var/run/docker.sock:/var/run/docker.sock \
  containrrr/watchtower \
  --label-enable

If using docker-compose:

watchtower:
  container_name: watchtower
  image: 'containrrr/watchtower:latest'
  restart: unless-stopped
  volumes:
    - /var/run/docker.sock:/var/run/docker.sock
  restart: unless-stopped
  networks:
    - main
  command: --label-enable

To mark images for auto-updating:

docker run -d --label=com.centurylinklabs.watchtower.enable=true someimage

Or if using docker-compose:

version: '3'

services:
  app:
    image: 'someimage'
    restart: always
    labels:
      - "com.centurylinklabs.watchtower.enable=true"

Watchtower will check periodically for newer images and will restart services/containers with new image.

Docker Compose

See docs for installing.

brew install docker-compose

Given a docker-compose.yml in the current directory, starting all containers:

docker-compose up

Or to start them as a daemons (in the background):

docker-compose up -d

Example docker-compose.yml

version: "3.7"

services:
  nats:
    image: nats-streaming:latest
    entrypoint:
    - /nats-streaming-server
    - -cid
    - amethyst-cluster
    ports:
    - "4222:4222"
    - "8222:8222"
    - "6222:6222"
    restart: always
    tty: true
    networks:
      - main

  mysql:
    image: mysql:8.0
    ports:
      - "3306:3306"
    restart: always
    tty: true
    environment:
      MYSQL_DATABASE: mydb
      MYSQL_USER: myuser
      MYSQL_PASSWORD: mypass
      MYSQL_ROOT_PASSWORD: root
    volumes:
      - db-data:/var/lib/mysql
    networks:
      - main

  redis:
    image: redis:latest
    ports:
      - "6379:6379"
    restart: always
    tty: true
    networks:
      - main

  myimage:
    image: myorganization/myimage:latest
    build: .
    depends_on:
      - nats
      - mysql
      - redis
    environment:
      ENV: stage
      LANG: C.UTF-8
      NATS_SERVERS: "nats://nats:4222"
      VOLUME_PATH: "/tmp/dont_care"
    networks:
      - main
    command: bash /path/to/custom-command.sh
    volumes:
      - .:/tmp/dont_care

volumes:
  db-data:

networks:
  main:
    external:
      name: main

Dropbox

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Remove all shared links

Go to https://www.dropbox.com/share/links, open the browser’s JavaScript console (⌘ + ⎇ + I) and paste the following:

$$("#links-list .mc-popover-trigger").forEach((n) => {
  console.log("delete", n);
  n.click();
  $(".delete-link").click();
  $(".button-primary").click();
});

Screenshots Sync on MacOS

In case Dropbox’s “Share Screenshots” option isn’t working (since it periodically stops working), or in case you don’t want to automatically share a link to synchronized screenshots …

Solution 1: Configure MacOS’s Screen Capture

Change the filename prefix:

defaults write com.apple.screencapture name "Screenshot"

Change the location:

defaults write com.apple.screencapture location /Users/alex/Dropbox/Screenshots/

Finally, refresh settings:

killall SystemUIServer

Solution 2: Sync via Script

Have a script in /usr/local/bin/detect-screenshots.rb:

#!/usr/bin/env ruby

Dir["/Users/alex/Desktop/Screen*at*.png"].each do |f|
  if f =~ /(\d{4}-\d{2}-\d{2})\s+at\s+(\d{2}\.\d{2}\.\d{2})/
    cmd = "mv \"#{f}\" \"/Users/alex/Dropbox/Screenshots/Screenshot #{$1} #{$2}\.png\""
    puts cmd
    `#{cmd}`
  end
end

Then add this file in ~/Library/LaunchAgents/alex.screenshot.detect.plist





    Label
    alex.screenshot.detect
    EnableGlobbing
    
    ProgramArguments
    
        /usr/local/bin/detect-screenshots
    
    WatchPaths
    
        /Users/alex/Desktop/
    
    ThrottleInterval
    5
    StandardOutPath
    /Users/alex/Library/Logs/detect-screenshots.log
    StandardErrorPath
    /Users/alex/Library/Logs/detect-screenshots.log

Then load it:

launchctl load -w ~/Library/LaunchAgents/alex.screenshot.detect.plist

Emacs

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Installation

My preferred installation on macOS:

brew install emacs --cask

This installs:

App '/Applications/Emacs.app'.
Binary '/usr/local/bin/emacs'.
Binary '/usr/local/bin/ebrowse'.
Binary '/usr/local/bin/emacsclient'.
Binary '/usr/local/bin/etags'.

GOTCHA: make sure these are on the system path and have priority over the system’s Emacs.

Settings

git clone https://github.com/alexandru/emacs.d ~/.emacs.d

See repo.

Emacs Server as MacOS Service

Create ~/Library/LaunchAgents/alex.emacs.plist:




  
    KeepAlive
    
    Label
    alex.Emacs
    ProgramArguments
    
      /usr/local/bin/emacs
      --fg-daemon
    
    RunAtLoad
    
    UserName
    replace_me_with_mac_username

The service can then be loaded via:

launchctl load -w ~/Library/LaunchAgents/alex.emacs.plist

Or unloaded via:

launchctl unload ~/Library/LaunchAgents/alex.emacs.plist

Script for running EmacsClient

Placed in ~/bin/run-emacsclient:

#!/usr/bin/env bash

if [ -z "$EMACSCLIENT_OPTS" ]; then
  EMACSCLIENT_OPTS="-nc"
fi

if [ $# -eq 0 ]; then
  COMMAND='/usr/local/bin/emacsclient '$EMACSCLIENT_OPTS' -e "(if (display-graphic-p) (x-focus-frame nil))"'
else
  COMMAND='/usr/local/bin/emacsclient '$EMACSCLIENT_OPTS' "$@"'
fi

if [ -z "$(shopt | grep login_shell)" ]; then
  echo "$COMMAND" | exec bash --login -s "$@"
else
  eval "exec $COMMAND"
fi

And a corresponding ~/bin/run-emacs-client-cli to force the CLI mode in the terminal, instead of opening a buffer in some opened GUI window:

#!/usr/bin/env bash

export EMACSCLIENT_OPTS='-t'
exec run-emacsclient "$@"

Bash/Zsh Settings

# Default zsh keybindings (emacs; might want to switch to vim later)
bindkey -e

# Adding Emacs to PATH
export PATH="$PATH:~/Applications/Emacs.app/Contents/MacOS/bin:/Applications/Emacs.app/Contents/MacOS/bin:~/Applications/Emacs.app/Contents/MacOS:/Applications/Emacs.app/Contents/MacOS"

# Default editor
export EDITOR="$HOME/bin/run-emacsclient-cli"
export VISUAL="$EDITOR"
export ALTERNATE_EDITOR="vim"

## Editor aliases
alias e="$HOME/bin/run-emacsclient-cli"
alias ew="$HOME/bin/run-emacsclient"
alias notes='$HOME/bin/run-emacsclient-cli -e "(deft)"'

emacs_open_buffer()
{
  run-emacsclient-cli -e "(let ((b (find-buffer-by-prefix \"$1\"))) nil)"
}
alias eb=emacs_open_buffer

Troubleshooting

Failed to verify signature

In my case Emacs was complaining that key 066DAFCB81E42C40 is missing.

I managed to solve it by running:

gpg --keyserver hkp://keys.gnupg.net --recv-keys 066DAFCB81E42C40

Afterwards starting Emacs from the command line might be a good idea.

General unhappiness

brew uninstall emacs

Then download VS Code.

Resources

The Emacs Lisp Style Guide

Email

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Send email from localhost

brew install swaks

swaks --auth \
	--server smtp.mailgun.org \
	--au postmaster@mail.mydomain.com \
	--ap password \
  --from alex@mail.mydomain.com \
	--to user@domain.com \
	--h-Subject: "Hello" \
	--body 'World!'

Via Python script

See: send-mail.py

Firefox

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at April 10, 2025, created at August 24, 2020.

Cool Extensions

Settings

about:config

Auto-sync about:config settings

Source: https://www.addictivetips.com/web/sync-about-config-preferences-with-firefox-sync/

For each setting to be synched, add:

services.sync.prefs. true

Examples:

services.sync.prefs.toolkit.legacyUserProfileCustomizations.stylesheets

services.sync.prefs.media.hardwaremediakeys.enabled

Activate compact mode (after Proton)

In about:config:

browser.compactmode.show = true

Source: https://support.mozilla.org/en-US/kb/compact-mode-workaround-firefox

Restore Pinned Tabs on Demand

Note sure how to prevent the pinned tabs from opening at all, but at least this delays them loading, until you activate the tabs:

browser.sessionstore.restore_pinned_tabs_on_demand = true

services.sync.prefs.browser.sessionstore.restore_pinned_tabs_on_demand = true

Hide Native Tabs (for Tree Style Tabs)

https://medium.com/@Aenon/firefox-hide-native-tabs-and-titlebar-f0b00bdbb88b

In about:config set:

toolkit.legacyUserProfileCustomizations.stylesheets = true

// For syncing the setting
services.sync.prefs.toolkit.legacyUserProfileCustomizations.stylesheets = true

Then in the /chrome/userChrome.css:

/* hides the native tabs */
#TabsToolbar {
  visibility: collapse;
}

#sidebar-header {
  visibility: collapse !important;
}

Suggest JavaScript Bookmarklets

browser.urlbar.filter.javascript = true

services.sync.prefs.browser.urlbar.filter.javascript = true

Source

Enable calculator

Source: https://xoxo.zone/@annika/111459732964070961

browser.urlbar.suggest.calculator = true

services.sync.prefs.browser.urlbar.suggest.calculator = true

All about: Pages

Docs

Git

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Commands

Cleanup a local repository of all untracked files:

git clean -dfx

Throw away all uncommitted changes:

git reset --hard HEAD

Large files support

Resources:

Installation:

brew install git-lfs

In the git repository:

git lfs install

To add file extensions to track via “lfs”:

git lfs track "*.psd"

git-sync

GitHub

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Tools

For creating labels: https://github.com/integratedexperts/github-labels/

Trigger manual build

We can use GitHub’s API to trigger a custom event, e.g:

curl --fail \
  -XPOST -u "${GH_USERNAME}:${GH_TOKEN}" \
  -H "Accept: application/vnd.github.everest-preview+json" \
  -H "Content-Type: application/json" \
  https://api.github.com/repos/${REPO_ORGANIZATION}/${REPO_NAME}/dispatches \
  --data '{"event_type": "custom_event"}'

Set the GH_USERNAME, GH_TOKEN, REPO_ORGANIZATION and REPO_NAME environment variables. Might also want to set the custom_event identifier to something that makes sense for you.

Then in GitHub Actions to trigger an action in response to this custom_event:

on:
  repository_dispatch:
    types: [custom_event]

GNU Screen

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Links

Documentation

Cheatsheet

Start a new session:

Start a new named session:

screen -S

List sessions:

screen -ls

Re-attach session:

screen -r

Main commands:

Shortcuts menu: Ctrl-a ?
Command mode: Ctrl-a :
Detach session: Ctrl-a d

Window management:

Create a new window: Ctrl-a c
Kill current window: Ctrl-a k
Next window: Ctrl-a n
Previous window: Ctrl-a p
Jump to window: Ctrl-a 0-9
Split vertical: Ctrl-a |
Split horizontal: Ctrl-a S
Focus next region: Ctrl-a ^
Quit split screen mode: Ctrl-a Q

Custom ~/.screenrc

shell -$SHELL

# Buffer size
defscrollback 50000

# Allow bold colors - necessary for some reason
attrcolor b ".I"

# Tell screen how to set colors. AB = background, AF=foreground
termcapinfo xterm 'Co#256:AB=\E[48;5;%dm:AF=\E[38;5;%dm'

# Erase background with current bg color
defbce "on"

# Enable 256 color term
term xterm-256color

# Very nice tabbed colored hardstatus line
hardstatus string '%{= Kd} %{= Kd}%-w%{= Kr}[%{= KW}%n %t%{= Kr}]%{= Kd}%+w %-= %{KG} %H%{KW}|%{KY}%101`%{KW}|%D %M %d %Y%{= Kc} %C%A%{-}'

#
## Control-^ (usually Control-Shift-6) is traditional and the only key not used by emacs
escape ^^^^
#
## do not trash BackSpace, usually DEL
bindkey -k kb
bindkey -d -k kb
#
## do not trash Delete, usually ESC [ 3 ~
bindkey -k kD
bindkey -d -k kD
  
# Hide hardstatus: ctrl-a f 
bind f eval "hardstatus ignore"
# Show hardstatus: ctrl-a F
bind F eval "hardstatus alwayslastline"

Haskell

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Educational Resources

State of the Haskell ecosystem: describes the best tools available
What I Wish I Knew When Learning Haskell
Haskell without the theory
Haskell: Build Tools
Haskell Study Plan
Type Classes

Books

Blog articles

Tools

hlint
ghcid: very basic IDE engine based on ghci
IntelliJ-Haskell
Haskell for Mac

iTerm2

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 2, 2022, created at August 24, 2020.

Configure opening of file paths (semantic history)

In iTerm’s settings, goto Profiles -> Advanced -> Semantic History.

Opening files in IntelliJ IDEA + Visual Studio Code

First create IntelliJ IDEA’s command line launcher. Press ⇧ Shift + ⇧ Shift (twice) to bring up the Navigate -> Search Everywhere dialog. Then write “create command-line launcher” in the search box, to select the desired action, then press ⏎ Enter:

Now idea is installed on the command line, on MacOS this is tipically in /usr/local/bin/idea.

Similarly, in Visual Studio Code press ⌘ Cmd + P, type “install code command”, and press ⏎ Enter:

The idea command line utility isn’t compatible with iTerm’s settings, plus if we want to discriminate based on file type, an extra script is needed. Save this in $HOME/bin/iterm-goto:

#!/bin/sh

GOTO_FILE="$1"
GOTO_LINE="$2"
GOTO_CHAR="$3"

if ! [ -f "$GOTO_FILE" ]; then
    echo "ERROR: file path missing or invalid!" >&2
    exit 1
fi

# Discriminate based on file extension, open only .scala or .sbt files in IntelliJ IDEA ...
if [[ "$GOTO_FILE" =~ ^.*\.(scala|sbt)$ ]]; then
    EDITOR_PATH="$(which idea)"

    if [ -z "$IDEA_PATH" ]; then
        EDITOR_PATH="/usr/local/bin/idea"
    fi

    if ! [ -z "$GOTO_LINE" ]; then
        exec "$EDITOR_PATH" --line "$GOTO_LINE" "$GOTO_FILE"
    else
        exec "$EDITOR_PATH" "$GOTO_FILE"
    fi
else
    EDITOR_PATH="$(which code)"

    if [ -z "$EDITOR_PATH" ]; then
        EDITOR_PATH="/usr/local/bin/code"
    fi

    if ! [ -z "$GOTO_CHAR" ]; then
        exec "$EDITOR_PATH" --goto "$GOTO_FILE:$GOTO_LINE:$GOTO_CHAR"
    elif ! [ -z "$GOTO_LINE" ]; then
        exec "$EDITOR_PATH" --goto "$GOTO_FILE:$GOTO_LINE"
    else
        exec "$EDITOR_PATH" "$GOTO_FILE"
    fi
fi

Then in iTerm’s settings, goto Profiles -> Advanced -> Semantic History, and set Run command ... to:

$HOME/bin/iterm-goto \1 \2

Setup automatic dark mode

NOTE: this is intended for the stable 3.4.x versions, and isn’t needed in the 3.5.x betas.

Create this file in ~/Library/Application\ Support/iTerm2/Scripts/AutoLaunch/auto_dark_mode.py:

#!/usr/bin/env python3.7

import asyncio
import iterm2

async def changeTheme(connection,parts):
    theme_dark = "Dark Background"
    theme_light = "Light Background"
    print(parts)
    
    if "dark" in parts:
        preset = await iterm2.ColorPreset.async_get(connection, theme_dark)
    else:
        preset = await iterm2.ColorPreset.async_get(connection, theme_light)

    # Update the list of all profiles and iterate over them.
    profiles=await iterm2.PartialProfile.async_query(connection)
    for partial in profiles:
        # Fetch the full profile and then set the color preset in it.
        profile = await partial.async_get_full_profile()
        await profile.async_set_color_preset(preset)

async def main(connection):
    app = await iterm2.async_get_app(connection)
    window = app.current_window
    initial_theme = await app.async_get_theme()
    await changeTheme(connection,initial_theme)

    async with iterm2.VariableMonitor(connection, iterm2.VariableScopes.APP, "effectiveTheme", None) as mon:
        while True:
            # Block until theme changes
            theme = await mon.async_get()
            # Themes have space-delimited attributes, one of which will be light or dark.
            parts = theme.split(" ")
    
            await changeTheme(connection,parts)

iterm2.run_forever(main)

Credits: @FradSer.

JSON

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Command-line parsing

jq — command-line JSON processor.

Sorting in descending order by field:

bw list items | jq 'sort_by(.revisionDate)|reverse'

Tutorial:

Handle large JSONs effortlessly with jq

macOS

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at January 24, 2025, created at August 24, 2020.

Finder Shortcuts

Cmd + Shift + G: Go to Folder
Cmd + Shift + .: Toggle visibility of dot files

Useful Apps

Ice: Powerful menu bar manager for macOS, OSS alternative to Bartender;
Hot: for monitoring the CPU temperature;
Smart Scroll: makes the mouse more useful;
Turbo Booster Switcher: switches off “turbo boost” for Intel CPUs, prevents overheating;

Stop Apple Music / iTunes from starting on Play

Source: Stop iTunes From Launching When You Press Play On Your Mac’s Keyboard

launchctl unload -w /System/Library/LaunchAgents/com.apple.rcd.plist

Find which app is stealing focus

Answer from StackExchange:

#!/usr/bin/python

try:
    from AppKit import NSWorkspace
except ImportError:
    print "Can't import AppKit -- maybe you're running python from brew?"
    print "Try running with Apple's /usr/bin/python instead."
    exit(1)

from datetime import datetime
from time import sleep

last_active_name = None
while True:
    active_app = NSWorkspace.sharedWorkspace().activeApplication()
    if active_app['NSApplicationName'] != last_active_name:
        last_active_name = active_app['NSApplicationName']
        print '%s: %s [%s]' % (
            datetime.now().strftime('%Y-%m-%d %H:%M:%S'),
            active_app['NSApplicationName'],
            active_app['NSApplicationPath']
        )
    sleep(1)

Needs pyobjc:

pip install pyobjc

Resources / Troubleshooting

PRAM reset: https://support.apple.com/en-us/HT204063
SMC reset: https://support.apple.com/en-us/HT201295
System Integrity Protection:
- How to Disable System Integrity Protection (rootless) in Mac OS X
- Configuring System Integrity Protection
Force updates for older Macs

MySQL / MariaDB

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Start a Docker Instance

docker run --rm --name mariadb -e MYSQL_ROOT_PASSWORD=pass -p 3306:3306 mariadb:10.5

Note --rm deletes the container after stop. Also add -d to detach (daemon mode).

To connect to it:

docker exec -it mariadb mysql -uroot -ppass

Create user

CREATE USER 'myuser'@'%' IDENTIFIED BY 'password';

GRANT ALL PRIVILEGES ON mydatabase.* TO 'myuser'@'%';

Note: localhost used as the host only allows access from localhost, whereas % allows access from everywhere.

Create Database

After 8.0:

CREATE DATABASE mydatabase CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci;

Before 8.0:

CREATE DATABASE mydatabase CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

Version 5.7:

CREATE DATABASE mydatabase CHARACTER SET utf8 COLLATE utf8_general_ci;

Nix

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Install/Uninstall instructions

Install with:

sh <(curl https://nixos.org/nix/install) --darwin-use-unencrypted-nix-store-volume

To uninstall:

Remove the entry from fstab using sudo vifs
Destroy the data volume using diskutil apfs deleteVolume
Remove the nix line from /etc/synthetic.conf or the file

Resources

Aliases

alias nix-env-search="nix-env -qaP"
alias nix-env-install="nix-env -iA"
alias nix-env-update-all="nix-channel --update nixpkgs && nix-env -u '*'"
alias nix-up="nix-env -u"
alias nix-gc="nix-collect-garbage -d"

Nix-env Cheatsheet

List installed packages:

nix-env --query --installed

To search for packages:

https://nixos.org/nixos/packages.html?channel=nixpkgs-unstable

To install a certain package:

nix-env -iA nixpkgs.ripgrep

Uninstall:

nix-env -e tree ripgrep

List generations (all of the different versions of the nix-env profile):

nix-env --list-generations

To rollback to a previous version of the profile:

nix-env --rollback

Or pick a specific generation:

nix-env --switch-generation 2

To use a program without installing it, we can create a temporary environment with nix-shell (in this case tectonic is the name of the package we want):

nix-shell '' -A tectonic

To update all packages:

nix-channel --update nixpkgs
nix-env -u '*'

Nix-shell Cheatsheet

To enable nix-shell for a project, define a default.nix in the project’s root, like so:

# This imports the nix package collection,
# so we can access the `pkgs` and `stdenv` variables
with import  {};

# Make a new "derivation" that represents our shell
stdenv.mkDerivation {
  name = "fpinscala-courses";

  # The packages in the `buildInputs` list will be added to the PATH in our shell
  buildInputs = [
    # see https://nixos.org/nixos/packages.html to search for more
    pkgs.tectonic
    pkgs.cmake
  ];
}

Then execute nix-shell in the directory.

Org-mode

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Shortcuts

C-c a show agenda
C-c C-t rotate state (change TODO to DONE)
C-c C-s schedule
C-c C-x p set property (e.g. STYLE to habit)
M-x org-time-stamp-inactive for inserting the current date

For clock timing:

C-c C-x C-i: start clock
C-c C-x C-o: stop the clock
C-c C-x C-d: display times
M-x org-resolve-clocks

Repeated tasks

Documentation.

Using a +1m says the date shift is exactly one month:

** TODO Pay the rent
   DEADLINE: <2005-11-01 Tue +1m>

Using ++1w shifts the date by at least one week, but also by as many weeks as it takes to get this date into the future. However, it stays on a Sunday, even if you called and marked it done on Saturday:

** TODO Call Father
   DEADLINE: <2008-02-10 Sun ++1w>

Using .+1m will shift the date to one month after today:

** TODO Check the batteries in the smoke detectors
   DEADLINE: <2005-11-01 Tue .+1m>

DEADLINE vs SCHEDULING

Documentation

DEADLINE:

the task is supposed to be finished on that date
the agenda for today will carry a warning about the approaching or missed deadline

SCHEDULED:

you are planning to start working on that task on the given date
a reminder that the scheduled date has passed will be present in the compilation for today, until the entry is marked DONE

PostgreSQL

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 2, 2025, created at August 24, 2020.

Creating new database and user

Open the client:

psql -U postgres

Execute:

CREATE DATABASE yourdbname;
CREATE USER youruser WITH ENCRYPTED PASSWORD 'yourpass';
GRANT ALL PRIVILEGES ON DATABASE yourdbname TO youruser;
ALTER DATABASE yourdbname OWNER TO youruser;

Running in a Docker container

Setup for docker-compose.yaml:

services:
  postgresdb:
    container_name: postgresdb
    image: 'postgres:15-alpine'
    volumes:
      - 'postgres-db:/var/lib/postgresql/data'
    restart: unless-stopped
    env_file:
      - ./envs/postgres.env
    networks:
      - main

networks:
  main:
    name: main

volumes:
  postgres-db:

Where ./envs/postgres.env:

POSTGRES_PASSWORD="your-admin-password"

Backup and Restore

Assuming a Docker container, to create a backup:

docker exec -i postgresdb pg_dumpall -U postgres | gzip > /tmp/dump.sql.gz

To restore from that backup:

gunzip -c /tmp/dump.sql.gz | docker exec -i postgresdb psql -U postgres

Documentation

PostgreSQL Lock Conflicts;

Python

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Pyenv + Virtualenv

Requirements:

Installation via Homebrew:

brew install pyenv pyenv-virtualenv

List available versions:

pyenv install --list

Install a specific Python version:

pyenv install 2.7.16

Create a new virtualenv:

pyenv virtualenv 2.7.16 my_project_name

Uninstall a virtualenv:

pyenv uninstall my_project_name

To activate an environment manually:

pyenv activate my_project_name

To automatically switch virtualenv when switching to a project’s directory, go to the project’s directory and create .python-version:

echo "my_project_name" > .python-version

RSS / Atom feeds

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Readers

Web:

Feedly (web)
FreshRSS (web, open source, self-hosted)
Miniflux (web, open-source, self-hosted)
Newsblur (web, open source)

Native, MacOS:

Reeder
NetNewsWire (open source)

Native, Linux:

NewsFlash

Native, Android:

Recommendation: Newsblur

Newsblur is probably the best:

Mobile client included for Android/iOS, OK for tablets, readable, auto Dark Mode, good integration
Organizing with multiple categories per feed
Newsletters forwarding support
Filtering via “infrequent articles” and training
Easy to migrate away

Self-hosted recommendation: FreshRSS

FreshRSS is the best for self-hosting:

Very easy to install and manage via Docker
Responsive web design, can work on mobile without client
Exposes the Fever and the GReader APIs out of the box, compatible with Reeder and other clients

Annoyances:

Feeds can’t belong to multiple categories, making organization hard
Filtering support for dealing with noise is only rudimentary
Couldn’t find any Android clients that I liked (FeedMe is close)

Resources

Rust

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 15, 2024, created at August 24, 2020.

Installation

See documentation.

To update Rust:

rustup update

To uninstall:

rustup self uninstall

Tools, Libraries

Build tools:

rust-clippy: linting for catching common mistakes;
rustfmt: automatic code formatting;

Fun stuff:

Web:

Documentation

The Rust Programming Language: official book for beginners
Rust by Example: another official book
Learn Rust With Entirely Too Many Linked Lists
Asynchronous Programming in Rust
Rust Sokoban
Tour of Rust

Exercises

Rustlings

Tutorials

Choosing Rust - Intro to Rust and Ownership (YouTube video)
Beginning Game Development with Amethyst (YouTube video)

How-to

Cargo

To start a new project:

cargo new hello_world

To build:

carbo build

# To build for release:

cargo build --release

# Type checks (faster than "build"):

cargo check

To compile and execute the project:

cargo run

To update dependencies:

cargo update

To generate and show the documentation of all dependencies:

cargo doc --open

Language Server

rustup component add rls

Teach Kids to Code

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Platforms, engines, toys:

Alligator Eggs: offline games
Code Combat: learn typed code through a programming game, learn Python, JavaScript, and HTML as you solve puzzles
Code World (from Google): educational computer programming environment using Haskell (intro video)
CodinGame: challenge-based training platform for programmers where you can improve your coding skills with fun exercises
Godot game engine: provides a huge set of common tools, so you can just focus on making your game without reinventing the wheel
Kojo: open source learning environment, Scala programs
Lego Mindstorms EV3: programmable robotics kit
Lightbot: solve puzzles using programming
MecaBricks: publish and display 3D models made with LEGO bricks
Microsoft MakeCode / MakeCode Arcade: brings computer science to life for all students with fun projects, immediate results, and both block and text editors for learners at different levels
Ozobot: makes desk-friendly coding robots that come with infinite ways to create, learn, and share
PuzzleScript: open-source HTML5 puzzle game engine
PyGame: a cross-platform set of Python modules designed for writing video games
Scratch: Create stories, games, and animations
Sonic Pi: code-based music creation and performance tool
Sphero BOLT: programmable robot ball
Swift Playgrounds: revolutionary app for iPad and Mac that makes learning Swift interactive and fun
TidalCycles: make patterns with code, whether live coding music at algoraves or composing in the studio
Turing Tumble: a game where players build marble-powered computers to solve logic puzzles

Books:

Land of Lisp: learn to program in Lisp, one game at a time
Realm of Racket: learn to program in Racket, one game at a time
Teach Your Kids to Code: book and Udemy online course teaching to build apps and games in Python

Articles & Videos:

How to teach programming (and other things)? by Felienne Hermans
Kids Coding Interlude
Scratch Ted Talk
Why John Carmack thinks Racket is aces for beginning programmers

Courses:

Coder Dojo: a volunteer-led community of free programming workshops for young people between 7 and 17
Scratch: Programming for Kids (8+): MOOC from EdX

Games

libGDX: Desktop/Android/HTML5/iOS Java game development framework
- KTX: Kotlin extensions for the libGDX game framework

tmux shortcuts & cheatsheet

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

Intro

start new:

tmux

start new with session name:

tmux new -s myname

attach:

tmux a  #  (or at, or attach)

attach to named:

tmux a -t myname

list sessions:

tmux ls

kill session:

tmux kill-session -t myname

Kill all the tmux sessions:

tmux ls | grep : | cut -d. -f1 | awk '{print substr($1, 0, length($1)-1)}' | xargs kill

In tmux, hit the prefix ctrl+b (my modified prefix is ctrl+a) and then:

Sessions

:new  new session
s  list sessions
$  name session

Windows (tabs)

c  create window
w  list windows
n  next window
p  previous window
f  find window
,  name window
&  kill window

Panes (splits)

%  vertical split
"  horizontal split

o  swap panes
q  show pane numbers
x  kill pane
+  break pane into window (e.g. to select text by mouse to copy)
-  restore pane from window
⍽  space - toggle between layouts
 q (Show pane numbers, when the numbers show up type the key to goto that pane)
 { (Move the current pane left)
 } (Move the current pane right)
 z toggle pane zoom

Sync Panes

You can do this by switching to the appropriate window, typing your Tmux prefix (commonly Ctrl-B or Ctrl-A) and then a colon to bring up a Tmux command line, and typing:

:setw synchronize-panes

You can optionally add on or off to specify which state you want; otherwise the option is simply toggled. This option is specific to one window, so it won’t change the way your other sessions or windows operate. When you’re done, toggle it off again by repeating the command. tip source

Resizing Panes

You can also resize panes if you don’t like the layout defaults. I personally rarely need to do this, though it’s handy to know how. Here is the basic syntax to resize panes:

PREFIX : resize-pane -D (Resizes the current pane down)
PREFIX : resize-pane -U (Resizes the current pane upward)
PREFIX : resize-pane -L (Resizes the current pane left)
PREFIX : resize-pane -R (Resizes the current pane right)
PREFIX : resize-pane -D 20 (Resizes the current pane down by 20 cells)
PREFIX : resize-pane -U 20 (Resizes the current pane upward by 20 cells)
PREFIX : resize-pane -L 20 (Resizes the current pane left by 20 cells)
PREFIX : resize-pane -R 20 (Resizes the current pane right by 20 cells)
PREFIX : resize-pane -t 2 20 (Resizes the pane with the id of 2 down by 20 cells)
PREFIX : resize-pane -t -L 20 (Resizes the pane with the id of 2 left by 20 cells)

Copy mode:

Pressing PREFIX [ places us in Copy mode. We can then use our movement keys to move our cursor around the screen. By default, the arrow keys work. we set our configuration file to use Vim keys for moving between windows and resizing panes so we wouldn’t have to take our hands off the home row. tmux has a vi mode for working with the buffer as well. To enable it, add this line to .tmux.conf:

setw -g mode-keys vi

With this option set, we can use h, j, k, and l to move around our buffer.

To get out of Copy mode, we just press the ENTER key. Moving around one character at a time isn’t very efficient. Since we enabled vi mode, we can also use some other visible shortcuts to move around the buffer.

For example, we can use “w” to jump to the next word and “b” to jump back one word. And we can use “f”, followed by any character, to jump to that character on the same line, and “F” to jump backwards on the line.

   Function                vi             emacs
   Back to indentation     ^              M-m
   Clear selection         Escape         C-g
   Copy selection          Enter          M-w
   Cursor down             j              Down
   Cursor left             h              Left
   Cursor right            l              Right
   Cursor to bottom line   L
   Cursor to middle line   M              M-r
   Cursor to top line      H              M-R
   Cursor up               k              Up
   Delete entire line      d              C-u
   Delete to end of line   D              C-k
   End of line             $              C-e
   Goto line               :              g
   Half page down          C-d            M-Down
   Half page up            C-u            M-Up
   Next page               C-f            Page down
   Next word               w              M-f
   Paste buffer            p              C-y
   Previous page           C-b            Page up
   Previous word           b              M-b
   Quit mode               q              Escape
   Scroll down             C-Down or J    C-Down
   Scroll up               C-Up or K      C-Up
   Search again            n              n
   Search backward         ?              C-r
   Search forward          /              C-s
   Start of line           0              C-a
   Start selection         Space          C-Space
   Transpose chars                        C-t

Misc

d  detach
t  big clock
?  list shortcuts
:  prompt

Configurations Options:

# Mouse support - set to on if you want to use the mouse
* setw -g mode-mouse off
* set -g mouse-select-pane off
* set -g mouse-resize-pane off
* set -g mouse-select-window off

# Set the default terminal mode to 256color mode
set -g default-terminal "screen-256color"

# enable activity alerts
setw -g monitor-activity on
set -g visual-activity on

# Center the window list
set -g status-justify centre

# Maximize and restore a pane
unbind Up bind Up new-window -d -n tmp \; swap-pane -s tmp.1 \; select-window -t tmp
unbind Down
bind Down last-window \; swap-pane -s tmp.1 \; kill-window -t tmp

Resources:

Credits

Forked from: https://gist.github.com/MohamedAlaa/2961058

Windows 10

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at January 21, 2025, created at August 24, 2020.

Installation on Macbooks

Create bootable USB stick for installing Windows

1: Download the Windows ISO file from Microsoft’s website. 2: Identify the disk number of the USB drive: diskutil list 3: diskutil unmountDisk /dev/diskN 4: sudo dd if=/path/to/windows.iso of=/dev/rdiskN bs=1m

Boot Camp

To download the drivers:

From MacOS: Boot Camp Assistant -> Menu -> “Action” -> “Download Windows Support Software”
From Windows: https://github.com/timsutton/brigadier

Third-party utilities

To make the Macbook’s touchpad not suck: https://github.com/imbushuo/mac-precision-touchpad

Support for Hyper-Threading

Source: Hacker News comment
Documentation: Enabling VT-x on Mac Book Air in Bootcamp
Download: rEFInd

Set-up tutorials

A No-Bullshit Guide to Setting up Windows 10 (archive)

Custom Zsh Prompt

Alexandru Nedelcu — Mon, 24 Aug 2020 13:24:31 +0000

Article updated at September 1, 2022, created at August 24, 2020.

References:

# ------------------------------------------------------------------------------
# Customize PROMPT
# ------------------------------------------------------------------------------

autoload -Uz vcs_info
precmd_vcs_info() {
  vcs_info
}
precmd_functions+=(precmd_vcs_info)
setopt prompt_subst

export PROMPT="%F{196}%B%(?..?%? )%b%f%F{117}%2~%f%F{245} %#%f "
export RPROMPT="%B\$vcs_info_msg_0_%f%b"

zstyle ':vcs_info:git:*' formats '%F{240}%b %f %F{237}%r%f'
zstyle ':vcs_info:*' enable git

In iTerm2 make sure to enable Use built-in Powerline glyphs.

How this looks:

DNS Lookup - Check Domain’s DNS Records

Alexandru Nedelcu — Thu, 30 Jul 2020 10:00:27 +0000

Article updated at September 1, 2022, created at July 30, 2020.

For MX records (email):

dig mydomain.com MX

Checking records using different resolvers:

dig @1.1.1.1 mydomain.com MX # Cloudflare

dig @8.26.56.26 mydomain.com MX # Comodo

dig @8.8.8.8 mydomain.com MX # Google

dig @9.9.9.9 mydomain.com MX # Quad

dig @64.6.65.6 mydomain.com MX # Verisign

dig @192.71.245.208 mydomain.com MX # OpenNIC

dig @91.239.100.100 mydomain.com MX # UncensoredDNS

dig @77.88.8.7 mydomain.com MX # Yandex

dig @156.154.70.1 mydomain.com MX # Ultrarecursive DNS

dig @198.101.242.72 mydomain.com MX # Alternate DNS

dig @176.103.130.130 mydomain.com MX

Alexandru Nedelcu - Wiki

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