saw

Saw Ain't Watch

Execute a command repeatedly and display output

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Installation

🍺 Homebrew (Recommended for macOS)

# Tap the repository
brew tap jasonlotito/saw

# Install saw
brew install saw

Or install in one command: brew install jasonlotito/saw/saw

📥 Manual Install

# Download the script
curl -O https://raw.githubusercontent.com/jasonlotito/saw/main/saw
chmod +x saw

# Move to a directory in your PATH
sudo mv saw /usr/local/bin/

📦 Requirements

  • bash - Required (usually pre-installed)
  • fswatch - Optional, for file watching feature (brew install fswatch)

Why saw?

⏱️ Smart Timing

Unlike watch, saw waits for your command to finish before starting the interval timer.

  • No overlapping executions
  • Perfect for long-running commands
  • Predictable behavior

🎯 Execution Limits

Control exactly how many times or how long your command runs.

  • Max runs: -r 10
  • Max time: -m 5m
  • Environment variables supported

📡 Signal Triggering

Trigger immediate runs on demand without waiting for the interval.

  • Listen for SIGUSR1 signals
  • Perfect for event-driven workflows
  • Integrate with file watchers

👀 File Watching

Automatically run commands when files change using fswatch integration.

  • Zero manual setup
  • Recursive directory monitoring
  • Automatic cleanup

Examples

Basic Usage

# Watch file line count every 2 seconds
saw wc -l contributions.txt

# Custom interval of 5 seconds
saw -n 5 ls -la

# Using environment variable
INT=10 saw git status

Execution Limits

# Run exactly 10 times
saw -r 10 echo "hello"

# Run for 30 seconds
saw -m 30s date

# Run for 5 minutes with 10-second intervals
saw -m 5m -n 10 uptime

# Combine limits
saw -r 100 -m 5m ./my-script.sh

Signal Triggering

# Start saw in signal mode
saw -s npm test &

# Trigger immediate run from another terminal
kill -USR1 $(pgrep -f 'saw.*npm test')

# Combine with file watcher
fswatch -o ./src | xargs -n1 -I{} kill -USR1 $SAW_PID

File Watching

# Watch src directory and run tests on changes
saw -w ./src npm test

# Watch current directory and rebuild
saw --watch . npm run build

# Watch with custom interval between checks
saw -w ./app -n 10 'make build'

saw vs watch

Feature saw watch
Waits for command to finish ✓ ✗
Execution limits (max runs) ✓ ✗
Time limits (max time) ✓ ✗
Signal triggering (SIGUSR1) ✓ ✗
File watching integration ✓ ✗
Fixed interval execution ✗ ✓
Screen clearing ✓ ✓
Highlight differences ✓ ✓

Key difference: watch runs on a fixed interval regardless of command duration. saw waits for the command to complete, then waits the interval before running again.