Node version (or tell us if you're using electron or some other framework):

v6.9.5

ShellJS version (the most recent version/Github branch you see the bug on):

v0.7.7

Operating system:

macOS 10.12.4

Description of the bug:

Getting this error when trying to use grep -l option.

grep: option not recognized: l

Example ShellJS command to reproduce the error:

#! /usr/bin/env node
const shell = require('shelljs');
const fileList = shell.grep('-l', 'angular.module(\'App\').component', '*.js');