Tags
#php
#kotlin
#bash
#go
#sql
#rust
#typescript
#html
#java
#python
#files
#utils
#strings
#http
#concurrency
#async
#json
#arrays
#security
#types
#crypto
#database
#dates
#format
Bash
Generate a Random Password
Three approaches: pwgen (purpose-built), openssl (universally available), /dev/urandom + tr (zero deps). Pick by what's installed.
@admin
PHP
Stream Large CSV with Generator
Iterate over a CSV file row-by-row without ever loading the whole file into memory. Uses a generator so consumers can foreach naturally and PHP cleans up the file handle.
Java
JUnit 5 — Parameterized Tests
`@ParameterizedTest` runs the same test with multiple inputs. Use `@CsvSource`, `@MethodSource`, or `@EnumSource` for data. Eliminates copy-paste in test classes.
HTML
JSON-LD Structured Data (Schema.org)
JSON-LD is Google's preferred way to mark up structured data for rich search results. Drop it in a <script type="application/ld+json"> tag in <head>. Validate with Google's Rich Results Test.
SQL
ROW_NUMBER OVER PARTITION
Number rows within a partition — the most common "give me the Nth thing per group" pattern. Pair with a WHERE rn = 1 in an outer query to keep just the top row per group.
Bash
Read Single Keystroke Without Enter
For menus and confirm prompts where you want one-key response (no need to press Enter). -n 1 reads exactly one character, -s silences the echo.
Java
BufferedReader / BufferedWriter
For large files or line-oriented protocols, wrap a Reader/Writer in `Buffered*`. Reduces per-call overhead from many small reads to fewer large ones. Always close with try-with-resources.
Go
struct Tags for JSON Marshaling
Backtick string tags on struct fields control how `encoding/json` serializes them — rename to camelCase, omit zero values, skip entirely. The same tag system is used by many other libraries.
Kotlin
with — Scope an Existing Object
`with(x) { ... }` is `run` flipped: the receiver is the first argument. Reads naturally when you're doing several things to an existing object without chaining.
SQL
Conditional Aggregation (FILTER / CASE)
Count or sum subsets of rows in a single GROUP BY pass. PostgreSQL has the cleaner `FILTER` clause; everyone else uses `SUM(CASE WHEN ...)`.
Java
ExecutorService — Thread Pools
`ExecutorService` is the modern way to manage threads. Submit Callables/Runnables, get Futures back. Always shutdown the executor — and prefer try-with-resources on Java 19+ where ExecutorService is AutoCloseable.
HTML
Video Element with Captions
`<video>` with multiple `<source>` formats (MP4 + WebM), `controls`, `poster`, and a captions track via `<track kind="captions">`. All shipped with the browser — no JS player needed.
Go
Benchmarks with testing.B
`BenchmarkXxx(b *testing.B)` functions are run by `go test -bench`. `b.N` is the loop count the framework auto-tunes; report results in ns/op, allocs/op.
Kotlin
apply — Configure Object, Return Itself
`x.apply { ... }` runs the block with `x` as `this` (so you call methods/set properties directly) and returns `x`. The canonical builder-style configuration.
SQL
CREATE TABLE with Constraints
Declare data integrity rules right in the schema — primary keys, foreign keys, unique constraints, NOT NULL, CHECK constraints, defaults. The DB enforces them so application bugs can't corrupt your data.
SQL
RETURNING — Get Back What You Wrote
PostgreSQL `RETURNING *` returns the rows affected by an INSERT/UPDATE/DELETE — no separate SELECT round-trip needed. SQL Server has `OUTPUT`; MySQL added `RETURNING` in MariaDB and 8.0.31+.
Bash
Cron Entry From Script
Append a cron job idempotently — grep first to avoid duplicates on re-run. Doesn't require editing files manually.