watchex -- watch files or folder and run a command when files change.
watchex command [FILE]...
watchex will run a given command when given file(s) or folder(s) changes.
If FILE is not given, then it will watch current folder.
Key input Enter will terminate the command.
This will run 'grunt build' if any file change under the current folder.
watchex 'grunt build'
This will run 'make test' when lib/src.js or spec/src_spec.js changes.
watchex 'make test' lib/src.js spec/src_spec.js