makewatch

A Node.js CLI utility that watches a Makefile's dependency graph and automatically re-runs make whenever any dependency files change.

Features

• Automatic dependency extraction — Uses make -pn to parse the dependency graph, so all Makefile features work: variables, wildcards, shell calls, includes, pattern rules
• Smart file watching — Watches only the files that actually depend on the target, avoiding unnecessary rebuilds
• Wildcard support — When new files are created that match $(wildcard ...) or $(shell find ...) patterns, the tool detects them automatically
• Debounced rebuilds — Rapid file changes are grouped into a single build (default: 300ms debounce)
• Live output — See full make output in real-time with colors and progress indicators
• Graceful shutdown — Press Ctrl+C to cleanly close watchers and exit

Installation

Prerequisites

• Node.js >= 18.20.0
• make — Standard Unix build tool (usually pre-installed on Linux/macOS)

From release download

Download the latest release, extract it, and run the install script:

tar xzf makewatch-*.tar.gz
cd makewatch-*
./scripts/install.sh
makewatch [options] [target]

The scripts/install.sh script:

• Copies the package to /opt/makewatch (or ~/.local/opt/makewatch if /opt isn't writable)
• Installs dependencies
• Creates a makewatch command in /usr/local/bin/ (or ~/.local/bin if /usr/local/bin isn't writable)

The script automatically detects write permissions and uses user-local directories (~/.local/) if system directories aren't accessible.

You can override the defaults:

INSTALL_PREFIX=~/.local/opt/makewatch BIN_PREFIX=~/.local/bin ./scripts/install.sh

Usage

makewatch [options] [target]

Options:
  -C <dir>         Run make in this directory (default: current directory)
  -f <file>        Specify Makefile path
  -d <ms>          Debounce delay in milliseconds (default: 300)
  -v               Verbose output (show file change events)
  -h               Show help
  --version        Show version

Examples

Watch the default target and rebuild on changes:

makewatch

Watch a specific target in a subdirectory:

makewatch -C src build

Use a custom Makefile:

makewatch -f custom.mk

Verbose mode to see each file change:

makewatch -v all

Fast debounce (100ms) for responsive rebuilds:

makewatch -d 100 all

How it works

1. Parse dependencies — Run make -pn <target> to get make's internal database of all rules and their prerequisites
2. Extract file list — Walk the dependency tree from the target, collecting all file paths (excluding phony targets)
3. Watch files — Use chokidar (inotify-based) to monitor those files for changes
4. Rebuild — When any file changes, debounce for ~300ms then run make <target>
5. Re-parse — After each rebuild, re-parse dependencies to pick up newly-created files that match wildcard patterns

License

MIT