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references/rg-patterns.md

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+# rg - Ripgrep Patterns and Usage
+
+## Overview
+
+`ripgrep` (rg) is an extremely fast text search tool that respects `.gitignore` and supports regex patterns.
+
+## Basic Search
+
+```bash
+# Simple search
+rg 'pattern'
+
+# Case-insensitive
+rg -i 'pattern'
+
+# Case-sensitive (force)
+rg -s 'Pattern'
+
+# Smart case (case-insensitive unless uppercase present)
+rg -S 'pattern'
+```
+
+## File Type Filtering
+
+```bash
+# Search in specific file types
+rg -t py 'import'           # Python files
+rg -t rust 'fn main'        # Rust files
+rg -t js 'function'         # JavaScript files
+
+# Multiple types
+rg -t py -t js 'class'
+
+# Exclude types
+rg -T py 'pattern'          # Everything except Python
+
+# List available types
+rg --type-list
+```
+
+## Context Control
+
+```bash
+# Lines before match
+rg -B 2 'pattern'
+
+# Lines after match
+rg -A 5 'pattern'
+
+# Lines before and after
+rg -C 3 'pattern'
+
+# Both (different values)
+rg -B 2 -A 5 'pattern'
+```
+
+## Output Formatting
+
+```bash
+# Show line numbers (default in terminal)
+rg -n 'pattern'
+
+# Hide line numbers
+rg -N 'pattern'
+
+# Show column numbers
+rg --column 'pattern'
+
+# Show file paths only
+rg -l 'pattern'
+
+# Show files without matches
+rg --files-without-match 'pattern'
+
+# Count matches per file
+rg -c 'pattern'
+
+# Count total matches
+rg --count-matches 'pattern'
+```
+
+## Advanced Search
+
+### Word Boundaries
+
+```bash
+# Match whole words only
+rg -w 'word'
+
+# Example: find 'test' but not 'testing'
+rg -w 'test'
+
+# Regex word boundaries
+rg '\bword\b'
+```
+
+### Multiline Search
+
+```bash
+# Enable multiline mode
+rg -U 'pattern.*spanning.*lines'
+
+# Example: find function definitions
+rg -U 'def \w+\([^)]*\):\s*"""[^"]*"""'
+
+# Multiline with context
+rg -U -C 2 'pattern.*multiline'
+```
+
+### Fixed Strings
+
+```bash
+# Literal string search (no regex, faster)
+rg -F 'literal.string[with]special.chars'
+
+# Case-insensitive literal
+rg -F -i 'Literal String'
+```
+
+## File Filtering
+
+### By Path
+
+```bash
+# Search in specific directory
+rg 'pattern' src/
+
+# Multiple directories
+rg 'pattern' src/ tests/
+
+# Glob patterns
+rg -g '*.py' 'pattern'
+rg -g '**/*test*.py' 'pattern'
+
+# Multiple globs
+rg -g '*.{js,ts}' 'pattern'
+
+# Negative globs (exclude)
+rg -g '!*test*' 'pattern'
+rg -g '!*.min.js' 'pattern'
+```
+
+### Hidden and Ignored Files
+
+```bash
+# Search hidden files
+rg --hidden 'pattern'
+
+# Ignore .gitignore rules
+rg --no-ignore 'pattern'
+
+# Both
+rg --hidden --no-ignore 'pattern'
+
+# Search specific ignored directories
+rg --no-ignore -g 'node_modules/**' 'pattern'
+```
+
+## Regex Patterns
+
+### Basic Regex
+
+```bash
+# Any character
+rg 'a.c'              # matches 'abc', 'a2c', etc.
+
+# Character classes
+rg '[0-9]+'           # one or more digits
+rg '[a-zA-Z]+'        # letters only
+rg '[^0-9]'           # anything except digits
+
+# Anchors
+rg '^pattern'         # start of line
+rg 'pattern$'         # end of line
+rg '^pattern$'        # entire line matches
+```
+
+### Quantifiers
+
+```bash
+# Zero or more
+rg 'ab*c'             # ac, abc, abbc, etc.
+
+# One or more
+rg 'ab+c'             # abc, abbc, etc.
+
+# Zero or one
+rg 'ab?c'             # ac, abc
+
+# Exact count
+rg 'a{3}'             # aaa
+rg 'a{2,4}'           # aa, aaa, aaaa
+rg 'a{2,}'            # aa, aaa, aaaa, etc.
+```
+
+### Groups and Alternation
+
+```bash
+# Groups
+rg '(ab)+'            # ab, abab, ababab, etc.
+
+# Alternation
+rg 'cat|dog'          # cat or dog
+rg '(import|from) numpy'
+
+# Non-capturing groups
+rg '(?:http|https)://[^\s]+'
+```
+
+### Lookahead/Lookbehind
+
+```bash
+# Positive lookahead
+rg 'test(?=_unit)'    # 'test' followed by '_unit'
+
+# Negative lookahead
+rg 'test(?!_integration)'  # 'test' not followed by '_integration'
+
+# Positive lookbehind
+rg '(?<=def )\\w+'    # word after 'def '
+
+# Negative lookbehind
+rg '(?<!@)property'   # 'property' not preceded by '@'
+```
+
+## Replacement (with sed/perl)
+
+```bash
+# Find and replace (dry run)
+rg -l 'old_pattern' | xargs sed -n 's/old_pattern/new_pattern/gp'
+
+# Find and replace (in-place)
+rg -l 'old_pattern' | xargs sed -i '' 's/old_pattern/new_pattern/g'
+
+# Using perl for complex replacements
+rg -l 'pattern' | xargs perl -pi -e 's/old/new/g'
+```
+
+## JSON Output
+
+```bash
+# JSON output for scripting
+rg --json 'pattern'
+
+# Parse with jq
+rg --json 'pattern' | jq -r 'select(.type == "match") | .data.path.text'
+
+# Get line numbers
+rg --json 'pattern' | jq -r 'select(.type == "match") | "\(.data.path.text):\(.data.line_number)"'
+```
+
+## Statistics and Analysis
+
+```bash
+# Show statistics
+rg --stats 'pattern'
+
+# Count matches per file
+rg -c 'pattern' | sort -t: -k2 -nr
+
+# Find most common matches
+rg -o 'pattern' | sort | uniq -c | sort -nr
+
+# Files with most matches
+rg -c 'TODO' | awk -F: '$2 > 0' | sort -t: -k2 -nr | head
+```
+
+## Common Workflows
+
+### Code Search
+
+```bash
+# Find function definitions (Python)
+rg 'def \w+\(' -t py
+
+# Find class definitions
+rg 'class \w+' -t py
+
+# Find imports
+rg 'from .* import' -t py
+
+# Find TODO/FIXME comments
+rg '(TODO|FIXME|XXX|HACK):'
+
+# Find console.log statements
+rg 'console\.(log|error|warn)' -t js
+```
+
+### Configuration Search
+
+```bash
+# Find API keys (be careful!)
+rg -i 'api[_-]?key' -g '!*.md'
+
+# Find environment variables
+rg 'process\.env\.' -t js
+rg 'os\.getenv' -t py
+
+# Find hardcoded IPs
+rg '\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b'
+
+# Find URLs
+rg 'https?://[^\s<>"{}|\\^`\[\]]+'
+```
+
+### Dependency Analysis
+
+```bash
+# Find all imports of a module
+rg 'from mymodule import' -t py
+
+# Find all requires
+rg "require\(['\"].*['\"]\\)" -t js
+
+# Find external dependencies
+rg 'import.*from ["\'](?!\.)[^"\']+' -t py
+```
+
+### Testing
+
+```bash
+# Find test functions
+rg 'def test_\w+' -t py
+rg 'it\(["\']' -t js
+
+# Find assertions
+rg 'assert\w*\(' -t py
+rg 'expect\(' -t js
+
+# Find skipped tests
+rg '@skip|@pytest\.mark\.skip' -t py
+rg '\.skip\(' -t js
+```
+
+## Performance Tips
+
+1. **Use file type filters**: `-t` is faster than glob patterns
+2. **Use fixed strings when possible**: `-F` bypasses regex engine
+3. **Limit search scope**: Specify directories explicitly
+4. **Use word boundaries**: `-w` is faster than `\b` regex
+5. **Respect .gitignore**: Default behavior is already optimized
+
+## Interactive Workflows
+
+```bash
+# Search and edit
+rg -l 'TODO' | fzf | xargs $EDITOR
+
+# Search with preview
+rg --line-number 'pattern' | fzf --delimiter : --preview 'bat --color=always {1} --highlight-line {2}'
+
+# Multi-select and edit
+rg -l 'pattern' | fzf -m | xargs $EDITOR
+
+# Search, select, and replace
+FILE=$(rg -l 'pattern' | fzf)
+rg 'pattern' "$FILE" | fzf
+```
+
+## Configuration
+
+Create `~/.ripgreprc` for default options:
+
+```bash
+# Always show line numbers
+--line-number
+
+# Smart case search
+--smart-case
+
+# Follow symlinks
+--follow
+
+# Custom type definitions
+--type-add=web:*.{html,css,js}*
+```
+
+Use with: `export RIPGREP_CONFIG_PATH=~/.ripgreprc`
+
+## Comparison with grep
+
+| Task | grep | rg |
+|------|------|-----|
+| Case-insensitive | `grep -i` | `rg -i` |
+| Recursive | `grep -r` | `rg` (default) |
+| Show line numbers | `grep -n` | `rg -n` (default) |
+| Context | `grep -C 3` | `rg -C 3` |
+| File type | `grep --include='*.py'` | `rg -t py` |
+| Exclude pattern | `grep --exclude='test*'` | `rg -g '!test*'` |
+
+## Tips and Tricks
+
+### Shell Aliases
+
+```bash
+alias rgi='rg -i'                    # Case-insensitive
+alias rga='rg --hidden --no-ignore'  # Search everything
+alias rgl='rg -l'                    # Files only
+alias rgc='rg -c'                    # Count per file
+```
+
+### Functions
+
+```bash
+# Search and edit function
+rge() {
+  rg -l "$1" | fzf --preview "rg --color=always -C 5 '$1' {}" | xargs $EDITOR
+}
+
+# Search in specific file type
+rgt() {
+  TYPE=$1
+  shift
+  rg -t "$TYPE" "$@"
+}
+
+# Search with context and open
+rgf() {
+  rg --line-number "$1" | fzf --delimiter : --preview 'bat --color=always {1} --highlight-line {2}' | awk -F: '{print $1}' | xargs $EDITOR
+}
+```
+
+### Complex Patterns
+
+```bash
+# Email addresses
+rg '\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b'
+
+# Phone numbers (US)
+rg '\b\d{3}[-.]?\d{3}[-.]?\d{4}\b'
+
+# Hex colors
+rg '#[0-9a-fA-F]{6}\b'
+
+# Semantic versions
+rg '\b\d+\.\d+\.\d+\b'
+
+# Python function with type hints
+rg 'def \w+\([^)]*\) -> \w+:'
+
+# SQL queries in code
+rg -U 'SELECT.*FROM.*WHERE'
+```