#regex Clear
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 Filter Lines by Regex
grep -E (extended regex) is the right tool 95% of the time. Combine -i (case-insensitive), -v (invert), -n (line numbers), -B/-A (context lines).
SQL Pattern Matching — LIKE / ILIKE / SIMILAR
`LIKE` uses `%` (any string) and `_` (single char). PostgreSQL `ILIKE` is case-insensitive. For real regex, reach for `SIMILAR TO` (POSIX) or `~` (PostgreSQL).
JavaScript Validate Email Address
Validates an email address using a battle-tested regex that covers the vast majority of real-world addresses without being overly strict. For server-side code, pair this with a confirmation email step — client-side regex alone is not a security measure. Returns a boolean for easy conditional use.
PHP Word Count (UTF-8 aware)
Count words in a string in a way that works for any Unicode script — including those without ASCII whitespace. Built on the \p{L}\p{N} Unicode regex categories.