Beginner
190 entries match these filters
- 0355 TLS certificates explained What a certificate proves, who signs it, what the chain and expiry mean, and how to read any site's certificate from the… Beginner · Explains an idea · Any system Article TLS & certificates 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
- 0362 The 3-2-1 backup rule, and why a backup you never restored is not a backup Three copies, two kinds of media, one off-site: what the rule really protects against, how it maps to real tools, and why… Beginner · Explains an idea · Any system Article Strategy & restore drills 15 Oct 2026
- 0333 Fix: permission denied while trying to connect to the Docker daemon socket Every docker command fails with permission denied on /var/run/docker.sock. The daemon is fine; your user is not allowed to use its socket.… Beginner · Fixes an error · Linux Article Docker basics · Docker fixes 15 Oct 2026
- 0334 Fix: port is already allocated docker run or docker compose up fails with Bind for 0.0.0.0:8080 failed: port is already allocated. Find what holds the port, another… Beginner · Fixes an error · Linux, macOS, Windows Article Docker fixes · Processes & ports 15 Oct 2026
- 0335 Docker cleanup script with dry run and confirmation A bash wrapper around docker system prune that shows disk usage and lists what would be removed, supports a dry-run flag, and… Beginner · Step by step · Linux, macOS Script Docker basics · Shell scripting 15 Oct 2026
- 0340 Build and run a small Python web app in a container Write a tiny Flask app, give it a Dockerfile, build the image, run it with a published port, make a change and… Beginner · Guided project · Linux, macOS, Windows Article Basics · Docker basics · Images & registries 15 Oct 2026
- 0341 DNS, IP addresses and ports explained for beginners An IP address says which machine, a port says which program on it, and DNS turns names into addresses. The three ideas… Beginner · Explains an idea · Linux, macOS Article DNS, IP addresses & ports 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