Search & Regex

Fast search keeps Rust codebases navigable. ripgrep (rg) honors .gitignore, fd finds paths, and sed/awk wrangle build logs and CSV exports.

Recipe

rg "AppError" src/
rg -t rust "unwrap\(" --glob '!tests/**'
fd '\.rs$' src/
rg -l "sqlx::query" | xargs wc -l

When to reach for this:

Finding all uses before refactor
Auditing unwrap or unsafe in production paths
Locating stale TODOs before release

Working Example

# Find enum variants and impl blocks
rg "enum AppError" -A 20 src/
 
# Files importing axum but not in router module
rg -l "use axum" src/ | rg -v routes
 
# Count lines per module
fd . src -e rs | xargs wc -l | sort -n
 
# Transform CI log excerpt
sed -n '/error\[E/,+3p' ci.log

What this demonstrates:

-t rust filters file types
--glob excludes test trees
Pipelines combine rg, fd, and wc

Deep Dive

ripgrep Flags

Flag	Use
`-F`	Fixed string (no regex)
`-w`	Whole word
`-C 3`	Context lines
`--stats`	Match counts and timing
`-z`	Search in `.tar` etc.

vs IDE search

CLI search is scriptable in CI (e.g. fail if todo!() in src/ outside tests).

Gotchas

grep -r includes target/ - slow and noisy. Fix: use rg or --exclude-dir=target.
Regex special chars - . matches any char. Fix: rg -F for literal strings.
Case sensitivity - missed matches. Fix: -i when appropriate.
Huge binary false positives - rare in Rust repos. Fix: rg skips binaries by default.
sed in-place on macOS - different syntax. Fix: document GNU sed or use perl -pi.

Alternatives

Alternative	Use When	Don't Use When
`git grep`	Only tracked files	Need ignore-aware speed
`ast-grep`	Structural Rust search	Simple text lookup
rust-analyzer symbol search	Type-aware nav	CI scripting

FAQs

rg vs ag?

rg is faster and more maintained; default for Rust teams.

Search workspace members?

Run from workspace root; rg searches all crates unless scoped with -g.

Stack versions: This page was written for Rust 1.97.0 (edition 2024), Tokio 1.x, Axum 0.8, serde 1.0, sqlx 0.8, clap 4, and Polars 0.46+.

Working Example

# Find enum variants and impl blocks
rg "enum AppError" -A 20 src/
 
# Files importing axum but not in router module
rg -l "use axum" src/ | rg -v routes
 
# Count lines per module
fd . src -e rs | xargs wc -l | sort -n
 
# Transform CI log excerpt
sed -n '/error\[E/,+3p' ci.log

What this demonstrates:

-t rust filters file types

--glob excludes test trees

Pipelines combine rg, fd, and wc

Flag

Use

-F

Fixed string (no regex)

-w

Whole word

-C 3

Context lines

--stats

Match counts and timing

-z

Search in .tar etc.

Gotchas

grep -r includes target/ - slow and noisy. Fix: use rg or --exclude-dir=target.

Regex special chars - . matches any char. Fix: rg -F for literal strings.

Case sensitivity - missed matches. Fix: -i when appropriate.

Huge binary false positives - rare in Rust repos. Fix: rg skips binaries by default.

sed in-place on macOS - different syntax. Fix: document GNU sed or use perl -pi.

Alternative

Use When

Don't Use When

git grep

Only tracked files

Need ignore-aware speed

ast-grep

Structural Rust search

Simple text lookup

rust-analyzer symbol search

Type-aware nav

CI scripting

Search & Regex

Buscar en la documentación

Search & Regex