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

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

FAQs

Related

• regex - in-Rust regex
• Rust-based CLI tools
• Pipes & text processing
• Codebase orientation

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+.