What is Ripgrep?

ripgrep (binary: rg) is a line-oriented search tool written in Rust. It searches your current directory recursively for a regex pattern, while respecting your .gitignore rules.

Created by: Andrew Gallant ("BurntSushi") in 2016
Primary goal: Replace interactive grep -r usage for developers with something faster, smarter, and easier.

Why It Was Built

Traditional grep was designed in an era before:

• Modern multi-core CPUs
• Version-controlled projects with node_modules (300,000 files)
• Common project conventions for ignoring build artifacts

Every developer who has searched a repo with grep -r has typed a variant of:

grep -rn "pattern" . \
  --exclude-dir=node_modules \
  --exclude-dir=.git \
  --exclude="*.min.js" \
  --include="*.ts"

With rg, the equivalent is:

rg "pattern"

All those excludes are automatic because rg reads .gitignore.

Core Differences From grep

Behavior	grep default	rg default
Recursion	No (single file)	Yes
.gitignore	Not respected	Respected
Hidden files	Included	Excluded
Output coloring	No	Yes
Line numbers	No	Yes
File grouping	No	Yes
Threading	Single-core	Multi-core

Architecture: Why It Is So Fast

rg achieves its speed through three mechanisms:

1. Parallel Directory Traversal It uses a thread pool to search multiple directories simultaneously, fully utilizing multi-core processors.

2. Literal Optimization Before running the full regex engine, rg extracts any literal substrings from your pattern and uses SIMD instructions (via the memchr crate) to skip non-matching sections at CPU cache speed. The regex is only evaluated on lines that already contain the literal.

3. Smart Skip Lists Because rg reads .gitignore before it traverses directories, it prunes entire subtrees from the search queue before a single byte of those files is read from disk.

When to Use rg vs grep

Use rg for code and interactive searches:

• Searching a project repository
• Refactoring across many files
• Any search where you want readable, grouped output

Use grep for scripts and log streaming:

• Shell scripts deployed to servers without rg
• Piping tail -f output through a filter
• POSIX portability requirements