The Cobox — Knowledge is Growth
Tutorials, course notes and interview questions, free for everyone who wants to learn.
- All
- Python 133
- Tools 30
- Tutorials 20
- DATABASE 10
- PHP 8
- C & C++ 5
- Java 4
- Web Development 2
- General Blogs 1
-
Unix timestamps explained: seconds, milliseconds, time zones and the year 2038
What a Unix timestamp is, how to tell seconds from milliseconds, why 1970 is the starting point, how time zones fit in, and what the 2038 problem means, with examples you can check in the converter.
-
How a text diff works: compare two versions and see exactly what changed
How comparison tools find additions and removals, when to compare by line or by word, why invisible whitespace creates false differences, and how to use the Text Diff Checker for drafts, code and configs.
-
QR codes explained: error correction, size and the QR Code Generator
How a QR code stores data, what the four error-correction levels mean, how big to print one, and how to make a static code that never expires with no sign-up or tracking.
-
URL encoding explained: percent signs, %20 and when to use the URL Encoder
Why spaces become %20, which characters must be encoded, the difference between encoding a component and a whole URL, and how to avoid the classic double-encoding and plus-sign bugs.
-
Naming styles explained: camelCase, snake_case, kebab-case and the Case Converter
What camelCase, PascalCase, snake_case, kebab-case and CONSTANT_CASE are, which language or tool uses which, how title case and sentence case differ, and how to convert text in one click.
-
UUIDs explained: what version 4 UUIDs are and how to use them
What a UUID is, how a version 4 UUID is built, how unlikely a collision really is, when to use one as a database key, and how to generate them in bulk with the free UUID Generator.
-
Word Counter guide: count words, characters and reading time accurately
How words, characters, sentences and reading time are counted, why different tools give different numbers, and how to use the free Word Counter for essays, posts, meta descriptions and speeches.
-
JSON explained: validate, format and fix JSON with the JSON Formatter
What JSON is, the exact rules of valid JSON, the errors that break it most often, and how to validate, pretty-print and minify JSON with the free JSON Formatter.
-
How to create a strong password: length, randomness and the Password Generator
Why long random passwords beat clever ones, how password strength is measured in bits, how to use the free Password Generator, and the habits that actually protect your accounts.
-
Hidden characters in copied text: how to find and remove them
What zero-width spaces, non-breaking spaces and other invisible Unicode characters are, how they break code, forms and searches, and how to clean them with the free Invisible Character Cleaner.
-
Image Color Picker guide: read HEX and RGB values and build a palette from any photo
How to pick an exact colour from an image, what HEX and RGB values mean, how to check that two colours are readable together, and how to turn a photo into a small colour palette.
-
Hashing vs encoding vs encryption: a guide to the Hash & Encode Toolkit
The difference between hashing, encoding and encryption, what Base64, Base32, Base16 and SHA-256 are for, and how to use the free Hash & Encode Toolkit without making common security mistakes.