Reference

Dense, scannable lookup pages for commands, codes and syntax.

• chmod and File Permissions Cheat Sheet
• CIDR and Subnet Mask Cheat Sheet
• Common Network Ports Cheat Sheet
• Git Cheat Sheet
• HTTP Status Codes Cheat Sheet
• Linux Command Line Cheat Sheet

Plain-language explanations of how the things behind our tools work.

• How Base64 and Encoding Work
• How Calorie Needs Are Calculated
• How Color and Contrast Work
• How Compound Interest Works
• How Dates and Time Zones Work
• How Debt Payoff Strategies Work

Short definitions of technology, security and finance terms.

• 401(k)
• A1C (HbA1c)
• Amortization
• Annuity
• API
• APR