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Run commands when paths change.

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Run commands when paths change.


You'll need to install Node.js to use Watchy. Node comes packaged with npm, which is Node's package manager, and the preferred method of installing Watchy. After installing Node, simply type

npm install -g watchy

and you should have the

command available!


Usage: watchy [options] -- command arg1 arg2 ...

Run commands when paths change.

Options: -V, --version output the version number -d, --debounce [seconds] trigger a change at most every [seconds] seconds -k, --keep-alive restart the process if it exits -n, --no-color disable colored output -p, --use-polling use file polling even if fsevents or inotify is available -r, --restart [string] send [string] to STDIN to restart the process -R, --no-restart-after-signal disable process restart after being signaled and exited -s, --silent only output errors -S, --no-init-spawn prevent spawn when the watcher is created -t, --shutdown-signal [signal] use [signal] to shut down the process (default: "SIGTERM") -T, --reload-signal [signal] use [signal] to reload the process (defaults to shutdown signal) -w, --watch [pattern] watch [pattern] for changes, can be specified multiple times -W, --wait [seconds] send SIGKILL to the process after [seconds] if it hasn't exited -h, --help output usage information

The watch patterns are extglob format.


# The simple case
watchy -w 'lib/**/*' -- say "The lib directory changed."

Piping works as well

watchy -w 'styles/*/.less' -- bash -c "lessc styles/main.less | autoprefixer -o .tmp/styles/main.css"

Keep a process alive, restarting it as soon as it exits or "server.js"


watchy -kw server.js -- node server.js

Watch every file except dotfiles, the node_modules folder, and JSON files.

NOTE: Listen to as few files as possible for better performance.

watchy -w . -i '/.|/node_modules|.json$' -- node server.js

Tick tock!

watchy -ks -- bash -c 'date && sleep 1'

Tick tock (annoying version)!

watchy -ks -- bash -c 'say "In case you were wondering, it is date" && sleep 5'

$WATCHY_ACTION and $WATCHY_PATH are passed to the process.

watchy -w '*/' -- bash -c 'echo $WATCHY_ACTION $WATCHY_PATH'

=> modified /Users/casey/Documents/code/watchy/

Note: If you're using

for help with preprocessing, I'd recommend checking out my cogs project that is highly optimized for that case with in-memory processed file caching, directives, AMD support, and much more.


By default,

will send
to the running process after a change and wait for it to exit gracefully. By sending the
--wait|-W n
option, you can tell
to forcefully
the process after
seconds. In general, you should try to clean up connections in your processes like so:
process.on('SIGTERM', function () {
  // etc...

Node API

As of

watchy exposes a Node.js API.
const watchy = require('watchy');

watchy({ patterns: ['js/*/.js', 'css/*/.css'], onError: error => console.error(error), onChange: ({action, path}) => console.log(action, path), usePolling: true // defaults to false, but will fallback when fsevents are not available }).catch(er => { console.error(er); process.exit(1); });

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