How to use regex with ruplacer for capture groups?

Ruplacer uses Rust regex by default; specify patterns with parentheses for groups like '(\w+), (\w+)' and reference them with $1, $2 in the replacement string. Use single quotes to avoid shell interpretation.

Ruplacer vs sed for batch text replacement?

Ruplacer is safer for codebases as it provides dry-run previews, respects .gitignore, and skips binary files automatically. Sed is more universal and faster for simple, scripted replacements but lacks these safety features.

How to install ruplacer on Windows without Rust?

Download pre-compiled binaries from the GitHub releases page as assets, as Ruplacer offers standalone executables for Windows, Linux, and macOS without requiring Rust installation.

Can ruplacer handle very large files or directories?

Ruplacer walks directories efficiently and skips non-text files, but performance with extremely large files isn't detailed in the README; it may depend on system memory and Rust's regex engine.

How to filter files by type in ruplacer?

Use the --type flag with a file type like cpp or a glob pattern, or --type-not to exclude. View all supported types with ruplacer --type-list, which maps types to glob patterns.

Does ruplacer support Perl-style regex or other engines?

No, Ruplacer only supports Rust regex, which has some differences from Perl-style patterns (e.g., no \g for named groups). For literal strings, use --no-regex to avoid regex interpretation.

Open-Awesome

ruplacer

BSD-3-ClauseRustv0.10.0

A command-line tool to find and replace text in source files with regex support and case preservation.

GitHub

488 stars24 forks0 contributors

What is ruplacer?

Ruplacer is a command-line utility for safely finding and replacing text across source code files. It walks through directories, respects .gitignore rules, and provides a dry-run preview before applying changes, making it a reliable tool for code refactoring and batch text editing.

Target Audience

Developers and system administrators who need to perform safe, batch text replacements across codebases, particularly those working with multiple file types and wanting to avoid accidental file corruption.

Value Proposition

Developers choose Ruplacer for its safety-first approach with mandatory dry-run previews, robust regex support using Rust's regex engine, and intelligent file handling that automatically skips binary and non-UTF-8 files to prevent data loss.

Overview

Find and replace text in source files

Use Cases

Best For

Performing large-scale code refactoring with preview before committing changes
Batch renaming variables or functions across multiple source files safely
Updating literal strings or patterns in codebases while preserving case conventions
Filtering replacements by file type or glob patterns similar to ripgrep
Replacing text in projects with complex .gitignore rules without manual file listing
Using regex with capture groups for advanced pattern matching and replacement

Not Ideal For

Real-time editing workflows where immediate application of changes is required, as Ruplacer mandates a dry-run preview first.
Projects relying on IDE-integrated refactoring tools that offer semantic code analysis and live previews.
Teams that exclusively prefer graphical user interfaces over command-line utilities for batch operations.
Scenarios requiring undo functionality after replacements, as Ruplacer lacks built-in rollback features.

Pros & Cons

Pros

Dry-Run Safety

Defaults to a non-destructive preview mode, showing all proposed changes without writing to disk, and requires the explicit --go flag to apply, preventing accidental file corruption.

Advanced Regex Support

Uses Rust's regex engine for pattern matching, with support for capture groups referenced as $1, $2 in replacements, enabling complex text transformations.

Case Preservation

The --preserve-case flag intelligently maintains original casing styles like snake_case or CamelCase in replacements, useful for consistent code refactoring.

File Filtering

Allows selecting or ignoring files by type or custom glob patterns, similar to ripgrep, and honors .gitignore rules, making targeted replacements easy.

Cons

Rust Regex Limitations

Uses Rust regex, which differs from Perl-style regular expressions (e.g., group references as $1 instead of \1), potentially confusing users familiar with other regex flavors.

No Undo Functionality

Once changes are applied with --go, there is no built-in undo feature, requiring reliance on external backups or version control systems for rollback.

Installation Dependency

The primary installation method requires Rust and cargo, which can be a barrier for users without the Rust toolchain, though pre-compiled binaries are offered as an alternative.

Frequently Asked Questions

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