Cheat Sheets
All cheat sheets, comparisons and learning pages on this website collected in one place, grouped by topic. A cheat sheet is a compact overview of the most important commands or terms on a topic, for quick lookup instead of long searching.
Last updated: September 1, 2026
Programming
Programming Basics
Java, Python and C compared
Object Oriented Programming
Classes, objects and inheritance
SQL and Databases
Queries, tables and joins
Number Systems Basics
Decimal, binary and hexadecimal
System and Network
Linux Terminal Commands
The most important commands in a terminal style
Docker Commands
Containers, images and volumes
Docker Compose
Keywords for multiple services in one file
Administering IT Systems
BIOS, partitions and file systems
Networking Basics
TCP vs UDP, IPv4 vs IPv6
Network Diagnostics
Check your own connection locally
Keyboard Shortcuts
Useful shortcuts for everyday use
HTTP Status Codes
2xx to 5xx explained briefly
Home Network Basics
Router, DNS server and VPN at home
Security and Comparisons
Password Cracking Time
How long guessing takes
Security Myths
26 misconceptions corrected
Browser & Search Engines
Privacy compared
Android, iOS & GrapheneOS
Smartphone operating systems compared
Windows, Linux & macOS
Computer operating systems compared
Password Managers
Bitwarden, KeePassXC & 1Password
Cloud Providers
Nextcloud, Google Drive, OneDrive & more
Notes Apps
Standard Notes, Apple Notes, Notion & more
Email Providers
Gmail, Outlook, ProtonMail, Mailcow & more
VPN Providers
Mullvad, Proton VPN, NordVPN & more
Messengers
WhatsApp, Signal, Threema & more