# RegexPal

> Test and debug regex patterns against sample text. Use when checking match groups, validating patterns, generating replacements, linting syntax.

- Skill: `bytesagain/regexpal` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add bytesagain/regexpal`
- Raw SKILL.md: https://api.skillmd.com/api/skills/bytesagain/regexpal/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: bytesagain (https://skillmd.com/u/bytesagain)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/bytesagain/regexpal

---


# RegexPal

A real regex tester and toolkit for the terminal. Test patterns against text, find matches in files with highlighted output, perform replacements, extract capturing groups, and get human-readable explanations of regex syntax.

## Commands

| Command | Description |
|---------|-------------|
| `regexpal test <pattern> <text>` | Test if a regex matches text — reports full match, partial match, groups, and named groups |
| `regexpal match <pattern> <file>` | Find all matches in a file — highlights matches in red, shows line numbers and match count |
| `regexpal replace <pattern> <replacement> <file>` | Replace all matches in a file and output to stdout. Supports backreferences (`\1`, `\2`) |
| `regexpal extract <pattern> <file>` | Extract capturing groups from all matches in a file — shows each group value per match |
| `regexpal explain <pattern>` | Break down a regex pattern — lists character classes, groups, tokens, and quantifiers |

## Requirements

- `python3` (uses `re` stdlib module)

## Examples

```bash
# Test a pattern
regexpal test '^\d{3}-\d{4}$' '123-4567'

# Find emails in a file
regexpal match '\w+@[\w.-]+' contacts.txt

# Replace version numbers
regexpal replace 'v(\d+)\.(\d+)' 'v\1.$((\\2+1))' changelog.md

# Extract domain parts from emails
regexpal extract '(\w+)@(\w+\.\w+)' emails.txt

# Understand a complex pattern
regexpal explain '(?<=@)[\w.-]+'
```