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- 0454 Scan your own code and containers in CI: Gitleaks, Semgrep and Trivy Set up a GitHub Actions workflow that runs Gitleaks, Semgrep and Trivy on every push of your own project, learn what each… Intermediate · Step by step · Any system Article Pipelines, runners & hooks · Security testing & CTF 15 Oct 2026
- 0432 Try Sigma rules against your own logs Install the sigma-cli converter, take a rule from the public SigmaHQ library, convert it into a query for a log tool you… Intermediate · Step by step · Linux, macOS Article Logs · Security resources & detection 15 Oct 2026
- 0411 CORS explained, and how to fix the browser error The browser blocks a request from one origin to another unless the server allows it with Access-Control headers. Fix it in the… Intermediate · Step by step · Any system, Browser Article Making requests · Web servers & reverse proxies 15 Oct 2026
- 0420 cron and systemd timers: run something every night Schedule a script with crontab or a systemd timer: the five cron fields, environment and PATH pitfalls, logging, catching up missed runs… Beginner · Step by step · Linux Article cron & timers · Services & systemd 15 Oct 2026
- 0422 Dotfiles: keep your shell setup in git Put .bashrc, .zshrc, .gitconfig and your editor settings into a git repository so a new machine is set up in minutes: a… Intermediate · Step by step · Linux, macOS Article Modern command-line tools · Setup 15 Oct 2026
- 0409 Nginx as a reverse proxy with HTTPS Put Nginx in front of an app on localhost: a server block that proxies to the port, forwards the client headers, supports… Intermediate · Step by step · Linux Article Deploying sites · Web servers & reverse proxies 15 Oct 2026
- 0410 Caddy: HTTPS reverse proxy in five lines Caddy gets and renews TLS certificates on its own. Install it, write a Caddyfile with your domain and the port your app… Beginner · Step by step · Linux Article Deploying sites · Web servers & reverse proxies 15 Oct 2026
- 0373 Loki: ship and search logs Run Loki, Grafana Alloy and Grafana with Docker Compose, collect the systemd journal and /var/log files with a short Alloy configuration, and… Intermediate · Step by step · Linux Article Logs 15 Oct 2026
- 0381 pre-commit hooks: catch mistakes before they are committed Install the pre-commit framework, configure hooks for whitespace, YAML and JSON syntax, large files, leaked private keys, Python linting and shellcheck, run… Beginner · Step by step · Linux, macOS, Windows Article Pipelines, runners & hooks · Setup 15 Oct 2026
- 0386 Install Node.js on Linux, macOS and Windows Get Node.js and npm on any desktop OS. Use a version manager (nvm or fnm) when you work on several projects, or… Beginner · Step by step · Linux, macOS, Windows Article Installing languages & tools · Node.js 15 Oct 2026
- 0387 Install Python on Linux, macOS and Windows Install a current Python 3 with pip and venv on each desktop OS, check the version, and avoid the classic traps: python… Beginner · Step by step · Linux, macOS, Windows Article Environments & packages · Installing languages & tools 15 Oct 2026
- 0388 Install Go on Linux, macOS and Windows Install the Go toolchain from the official downloads or a package manager, set PATH so the go command and installed tools are… Beginner · Step by step · Linux, macOS, Windows Article Installing languages & tools 15 Oct 2026
- 0389 Install Java (OpenJDK) on Linux, macOS and Windows Install a current long-term-support OpenJDK with the compiler included, make java and javac available on the command line, and switch between versions… Beginner · Step by step · Linux, macOS, Windows Article Installing languages & tools 15 Oct 2026
- 0390 Install Git on Linux, macOS and Windows Install Git from your package manager, Xcode's command line tools or the Windows installer, confirm the version, and do the one-time configuration… Beginner · Step by step · Linux, macOS, Windows Article Installing languages & tools · Setup 15 Oct 2026
- 0391 Install Docker on Linux, macOS and Windows Docker Desktop or Docker Engine? Pick the right one for your OS, install it, and confirm with docker run hello-world. Covers the… Beginner · Step by step · Linux, macOS, Windows Article Docker basics · Installing languages & tools 15 Oct 2026
- 0392 Install Visual Studio Code on Linux, macOS and Windows Install VS Code from Microsoft's packages, Homebrew or winget, get the code command working in the terminal, and add the extensions you… Beginner · Step by step · Linux, macOS, Windows Article Command-line tools · Installing languages & tools 15 Oct 2026
- 0393 Install PostgreSQL on Linux, macOS and Windows Install the PostgreSQL server and the psql client on each desktop OS, start the service, connect as the postgres superuser and create… Beginner · Step by step · Linux, macOS, Windows Article Install & connect · Installing languages & tools 15 Oct 2026
- 0394 Install kubectl on Linux, macOS and Windows Install the Kubernetes command-line client with curl, a package manager or winget, verify it, and point it at a cluster with a… Beginner · Step by step · Linux, macOS, Windows Article Concepts · Installing languages & tools 15 Oct 2026
- 0395 Install Rust on Linux, macOS and Windows Install Rust the official way with rustup, which brings rustc, cargo and future updates, make sure a C linker is present, and… Beginner · Step by step · Linux, macOS, Windows Article Installing languages & tools 15 Oct 2026
- 0371 Where are the logs? journalctl, /var/log and container logs A practical map of where Linux programs write their logs and the commands to read them: journalctl filters, the classic files under… Beginner · Step by step · Linux Article Logs 15 Oct 2026
- 0372 Grafana: your first dashboard from Prometheus data Connect Grafana to a Prometheus server, build a four-panel host dashboard with PromQL queries, set units and thresholds, add an instance variable,… Beginner · Step by step · Browser, Linux, macOS Article Prometheus & Grafana 15 Oct 2026
- 0344 ufw and firewalld: open and close ports Allow and remove ports and services on the two standard Linux host firewalls, restrict a port to one source network, and make… Beginner · Step by step · Linux Article Firewalls · Networking & firewalls 15 Oct 2026
- 0345 SSH keys: create, copy and use them Generate an ed25519 key pair, install the public key on a server with ssh-copy-id, keep the private key protected with a passphrase… Beginner · Step by step · Linux, macOS, Windows Article Keys & config · SSH 15 Oct 2026
- 0352 Harden a fresh Linux server in 30 minutes The baseline for any new Debian, Ubuntu or RHEL-family server: updates on, a non-root user with sudo, SSH keys only, a firewall… Beginner · Step by step · Linux Article Server hardening · Users, sudo & hardening 15 Oct 2026
- 0353 fail2ban: block repeated failed logins Install fail2ban, enable the sshd jail with sane ban times, whitelist your own address, read the ban list, unban someone, and add… Intermediate · Step by step · Linux Article Server hardening · SSH 15 Oct 2026
- 0354 sudo rules: give a user exactly the rights they need Write sudoers rules with visudo: full admin for operators, a short list of commands for a deploy account, no-password rules for automation,… Intermediate · Step by step · Linux Article Secrets & access · Users, sudo & hardening 15 Oct 2026
- 0356 Free HTTPS with Let’s Encrypt and certbot Install certbot, get a trusted certificate for your domain and let it configure nginx or Apache, or just obtain the files for… Beginner · Step by step · Linux Article TLS & certificates 15 Oct 2026
- 0357 Keep secrets out of git: .env files, gitignore and what to do after a leak Load passwords and API keys from an untracked .env file, commit a safe .env.example instead, catch mistakes before they are pushed, and… Beginner · Step by step · Any system Article Housekeeping · Secrets & access 15 Oct 2026
- 0363 Restore drill: prove your backup works in 15 minutes A repeatable procedure to restore one file and one database from your newest backup into a scratch location, compare the result with… Intermediate · Step by step · Linux, macOS Article Backup tools · Strategy & restore drills 15 Oct 2026
- 0364 Schedule PostgreSQL and MySQL dumps with systemd timers Write one dump script for PostgreSQL and MySQL, run it from a systemd service and timer instead of cron, keep two weeks… Intermediate · Step by step · Linux Article Backup tools · PostgreSQL 15 Oct 2026
- 0365 Proxmox Backup Server: first setup and first restore Install Proxmox Backup Server, create a datastore and a backup user, connect it to Proxmox VE as storage, run the first VM… Intermediate · Step by step · Linux Article Backup & restore · Backup tools 15 Oct 2026
- 0328 Install Docker Engine on Ubuntu and Debian Set up Docker's official apt repository, install Docker Engine with the Compose and Buildx plugins, run hello-world and let your user run… Beginner · Step by step · Linux Article Docker basics · Packages & updates 15 Oct 2026
- 0330 Write a Dockerfile: FROM, COPY, RUN, CMD and multi-stage builds How a Dockerfile turns into an image layer by layer, what the main instructions do, how to order them for fast rebuilds,… Intermediate · Step by step · Linux, macOS, Windows Article Docker basics · Images & registries 15 Oct 2026
- 0331 docker compose for an app with a PostgreSQL database A compose.yaml that runs your application next to a PostgreSQL container, with a named volume for the data, a health check so… Intermediate · Step by step · Linux, macOS, Windows Article Docker Compose · Install & connect 15 Oct 2026
- 0332 Tag, push and pull images with Docker Hub and other registries How image names map to registries, how to log in, tag and push an image to Docker Hub, GitHub Container Registry or… Intermediate · Step by step · Linux, macOS, Windows Article Images & registries 15 Oct 2026
- 0342 Which process is using a port, and how to free it Find the program behind a busy port with ss, lsof or fuser, decide whether to stop it properly or kill it, and… Beginner · Step by step · Linux, macOS Article DNS, IP addresses & ports · Networking & firewalls 15 Oct 2026
- 0243 Database backup strategy: the 3-2-1 rule and testing restores Keep three copies of your data on two kinds of storage with one copy offsite, choose dump or snapshot methods per database,… Intermediate · Step by step · Linux Article Database operations · Security & access 15 Oct 2026
- 0233 Turn on MongoDB authentication and create least-privilege users A fresh MongoDB install accepts connections without a password. Create a user administrator, enable authorization, then give each application and backup job… Intermediate · Step by step · Linux Article Administration · Security & access 15 Oct 2026
- 0242 Database security checklist: access, encryption, exposure and patching A practical checklist for hardening any database server, with MongoDB and Redis examples: no public exposure, authentication, least privilege, TLS, protected backups,… Advanced · Step by step · Linux Article Database operations · Security & access 15 Oct 2026
- 0202 Back up and restore PostgreSQL with pg_dump, pg_restore and pg_dumpall Make logical backups of one database with pg_dump, of roles and the whole cluster with pg_dumpall, and restore them with pg_restore or… Beginner · Step by step · Linux Article Backup & restore 15 Oct 2026