WatchExec

Simple cross platform file watcher for running commands when files change.

Built with C#, .NET 10 and FileSystemWatcher API.

Features

• Cross platform
• Multiple watchers
• Recursive directory watching
• Regex based file matching
• Debounce support
• Live stdout and stderr streaming
• JSON config
• Token replacement in commands

---

Build

dotnet restore && dotnet build -c Release

Run

dotnet run -- watcher.config.json

If the config file does not exist in current directory, WatchExec creates an example config automatically.

---

Example Config

{
  "watchers": [
    {
      "name": "TypeScript Builder",
      "path": "./src",
      "includeSubdirectories": true,
      "regexPattern": ".*\\.(ts|tsx|js|jsx)$",
      "debounceMilliseconds": 500,
      "notifyFilters": ["FileName", "LastWrite"],
      "command": "bash",
      "arguments": ["-c", "echo Changed: {fullpath}"],
      "waitForExit": true,
      "workingDirectory": "."
    }
  ]
}

---

Config Fields

Field	Description
name	Watcher name
path	Directory to watch
includeSubdirectories	Watch subdirectories
regexPattern	Regex applied to normalized full paths
debounceMilliseconds	Delay before triggering command
notifyFilters	FileSystemWatcher notify filters
command	Executable or shell command
arguments	Command arguments
workingDirectory	Working directory for the process
waitForExit	Wait for command completion
internalBufferSizeKb	File watcher buffer size

---

Available Tokens

These tokens can be used inside commands and arguments.

Token	Description
{fullpath}	Full file path
{directory}	File directory
{filename}	File name
{name}	File name without extension
{extension}	File extension
{event}	Event type
{timestamp}	Unix timestamp
{oldfullpath}	Previous file path on rename
{oldfilename}	Previous file name on rename

---

Example Commands

Auto run tests on C# changes

{
  "name": "DotNet Tests",
  "path": "./tests",
  "regexPattern": ".*\\.cs$",
  "command": "dotnet",
  "arguments": ["test", "--nologo"],
  "waitForExit": true
}

Build Lux files

{
  "name": "Lux Build",
  "path": "./src",
  "regexPattern": ".*\\.lux$",
  "command": "lux",
  "arguments": ["build", "{fullpath}"]
}

---

Publish Self Contained

Linux

dotnet publish -c Release -r linux-x64 --self-contained true

Windows

dotnet publish -c Release -r win-x64 --self-contained true

macOS

dotnet publish -c Release -r osx-arm64 --self-contained true

---

Notes

• Uses normalized absolute paths for Regex matching
• Debouncing reduces duplicate file events
• Child process output is streamed live
• JSON comments and trailing commas are supported
• Multiple watchers can run at the same time