c9: grunt-watchify throws error "Fatal error: watch EMFILE" - gruntjs

Question

I have c9 workspace and I am running grunt with grunt-watchify to automatically create the bundle file. It was working fine when suddenly I get this error (debug is true on grunt-watchify):
./app/js/controller.js [ [ '.', 'app', 'js', 'controller.js' ] ]
./app/js/controller.js [ [ '.', 'app', 'js', 'controller.js' ] ]
stat [ '/home/ubuntu/workspace',
'./app/js/controller.js',
'=',
'./app/js/controller.js' ]
emit! match
matches[0] = { './app/js/controller.js': true }
emitting end [ './app/js/controller.js' ]
emit! end
Fatal error: watch EMFILE
And now it is not working. If I change watchify to browserify, it works.
This is my Gruntfile.js:
module.exports = function(grunt) {
grunt.initConfig({
pkg: grunt.file.readJSON('package.json'),
compass: {
dist: {
options: {
appDir: 'app/',
//sassDir: 'sass',
//cssDir: 'app/stylesheets'
}
},
dev: {
options: {
appDir: 'app/',
watch: true
}
}
},
concurrent: {
dev:
['watch', 'compass:dev']
},
watchify: {
dev: {
src: './app/js/controller.js',
dest: 'app/bundle.js',
debug: true
},
},
watch: {
css: {
files: '**/*.scss',
tasks: ['compass']
},
app: {
files: 'app/js/bundle.js',
options: {
livereload: true
}
}
},
browserify: {
dist: {
files: {
'app/bundle.js': [
'app/js/*.js',
]
}
},
},
bower: {
install: {
//just run 'grunt bower:install' and you'll see files from your Bower packages in lib directory
},
options: {
targetDir: './app/lib'
}
}
});
grunt.loadNpmTasks('grunt-concurrent');
grunt.loadNpmTasks('grunt-contrib-compass');
grunt.loadNpmTasks('grunt-contrib-watch');
grunt.loadNpmTasks('grunt-browserify');
grunt.loadNpmTasks('grunt-watchify');
grunt.loadNpmTasks('grunt-bower-task');
grunt.registerTask('default',['bower:install', 'watchify', 'concurrent']);
grunt.registerTask('heroku',['compass:dist', 'browserify', 'bower:install']);
}

Answer 1

EMFILE means that there are too many files open. This is most likely caused by a process that is still running and has somehow opened many files. You can use "ps aux" to check which processes are running. In Cloud9 you can see this also in the process manager via the Tools menu (Tools > Process Manager). If you see any processes that look suspicious, such as node processes running, you can kill them via the process manager UI or by typing "kill " where is the process id of the process you which to kill. After that you should be able to run grunt again without the EMFILE error. (Assuming that grunt is not causing the issue itself).