Bash

Read File Line-By-Line (the safe way)

The classic `for line in $(cat file)` is wrong — it word-splits and globbing fires on filenames. Use `while IFS= read -r line` with input redirection.

56m ago 0

JavaScript

Random Hex Color

Generates a random 6-digit hex colour string. Useful for seeding avatar backgrounds, chart series colours, placeholder UI elements, and testing colour-dependent components. The crypto version produces a more unpredictable result suitable for generating unique palette tokens.

56m ago 0

Kotlin

Sealed Interfaces (Kotlin 1.5+)

Like sealed classes, but for interfaces — and a class can implement multiple sealed interfaces. Cleaner state modeling when you want "this is both a Loadable and a Cacheable".

56m ago 0

Bash

Get Public IP Address

Several free services return your public IP as plain text. Useful when scripts running behind NAT need to know what address the outside world sees.

56m ago 0

Go

time.Ticker — Periodic Tasks

`time.NewTicker(d)` fires on a channel every `d` interval. Combine with select + a done channel for a clean way to run periodic work that can be cancelled.

56m ago 0

Python

Safe JSON Read/Write

Idiomatic helpers for reading + writing JSON to disk, with atomic writes and pretty-printed output. Catches the common "edit and save → corrupt file on crash" failure mode.

56m ago 0

JavaScript

Promise All with Concurrency Limit

Runs an array of async tasks with a maximum concurrency cap, preventing you from firing hundreds of requests simultaneously. Processes items in batches, moving to the next as slots free up. Essential when hitting rate-limited APIs or processing large datasets without overwhelming the server.

56m ago 0

PHP

Partition Array Into Two Buckets

Split an array into [matches, non-matches] using a predicate callback. Single pass, preserves order, returns two lists.

56m ago 0

Bash

Create User With Sensible Defaults

Provision a new user account with a home directory, default shell, and sudo membership. Idempotent — re-running on an existing user is a no-op.

56m ago 0

Bash

Sum a Column with awk

Awk's default field splitter is whitespace; pass a single character with -F. Perfect for summing the Nth column of a log file or CSV.

56m ago 0

TypeScript

Environment Variable Validator

Validate process.env at boot-time and exit fast if anything's missing. The returned object is typed so the rest of the code reads `env.DATABASE_URL` instead of `process.env.DATABASE_URL!`.

56m ago 0

Go

Custom Generic Constraints

Type constraints are interfaces with type sets. Use them to express "any numeric" or "any ordered" without resorting to `any`.

56m ago 0

TypeScript

invariant() — Always-On Assertion

Throw if a condition is false, with TypeScript narrowing the type afterwards. Replaces ad-hoc `if (!x) throw` ladders and gives you type-safe guards in one line.

56m ago 0

PHP

Slack Incoming-Webhook Notification

Fire a quick notification to a Slack channel via an incoming webhook URL. Includes basic markdown-style mentions and an attachment color for severity.

56m ago 0

Rust

Result Combinators + the ? Operator

`Result<T, E>` chains like `Option`. The `?` operator unwraps `Ok` or early-returns the `Err`, converting via `From` so callers can use one error type for many sources.

56m ago 0

TypeScript

Chunk Array Into Fixed-Size Pieces

Split an array into chunks of `size` items. Common building block for batch APIs — "send 50 rows per request" — and for paginated grids.

56m ago 0

Java

Stream Basics — filter / map / collect

The fluent pipeline for transforming collections. `filter` keeps matching elements, `map` transforms each one, `collect(toList())` materializes the result.

56m ago 0

Kotlin

Star Projections (List<*>, etc.)

`List<*>` means "list of something I don't need to know exactly" — read-only with Any? as element type. Useful when you genuinely don't care about the parameter.

56m ago 0

Python

chunked — Split Iterable into Fixed-Size Pieces

Lazy chunker that works on any iterable, not just lists. Common building block for batch APIs — "send 50 rows per request" — without loading the source into memory.

56m ago 0

HTML

Skip-to-Main-Content Link

Keyboard users (and screen-reader users) tab through every nav link before reaching content. A skip-link as the first focusable element jumps straight to <main>. Required for WCAG 2.1 AA.

56m ago 0

TypeScript

URL Builder with Type-Safe Query

Build URLs with a clean query-param API. Skips null/undefined automatically, encodes everything, and accepts arrays for repeated keys. Avoids manual string concatenation.

56m ago 0

Bash

SSH to Multiple Hosts in Parallel

Run the same command on a fleet of hosts. Three patterns: serial loop (simplest), GNU parallel (fastest), pssh (purpose-built).

56m ago 0

Bash

Unique While Preserving Order

`sort -u` re-orders. `awk '!seen[$0]++'` is the classic order-preserving dedupe — and it's a single line.

56m ago 0

Go

Read File — Whole / Lines / Bytes

Three common patterns: load it all (`os.ReadFile`), iterate line-by-line with `bufio.Scanner`, or stream chunks via `io.Reader`. Pick by file size.

56m ago 0

Java

Optional Chains — flatMap, filter

`flatMap` lets you chain Optional-returning methods without nested `if`. `filter` short-circuits to empty if the predicate fails. The functional equivalent of safe-navigation `?.`.

56m ago 0

SQL

Views and Materialized Views

A view is a named query — no data stored. A materialized view caches the result; refresh it on demand. Great for expensive joins or aggregations that don't need to be real-time.

56m ago 0

Python

take / drop / takewhile

Take the first N items of an iterable (or while a predicate holds). drop is the complement. Lazy via islice + itertools.dropwhile — works on infinite generators.

56m ago 0

Kotlin

fold and scan

`fold` accumulates from a seed across all items. `runningFold` / `scan` yields every intermediate accumulator value — running totals, cumulative metrics.

56m ago 0

Bash

Sort by a Specific Column

Sort takes -k for column-based ordering and -t to set the delimiter. -h sorts human-readable sizes ("1.5G", "300K") correctly.

56m ago 0

Bash

Find Largest Files and Directories

Quick "where did all my disk go?" answer. du sorts by size, ncdu (interactive) is better for exploration.

56m ago 0