LCSOGthb / Tools

var EventEmitter = require('events').EventEmitter;

var spawn = require('child_process').spawn;

var path = require('path');

var dirname = path.dirname;

var basename = path.basename;

var fs = require('fs');

/**

 * Inherit `Command` from `EventEmitter.prototype`.

 */

require('util').inherits(Command, EventEmitter);

/**

 * Expose the root command.

 */

exports = module.exports = new Command();

/**

 * Expose `Command`.

 */

exports.Command = Command;

/**

 * Expose `Option`.

 */

exports.Option = Option;

/**

 * Initialize a new `Option` with the given `flags` and `description`.

 *

 * @param {String} flags

 * @param {String} description

 * @api public

 */

function Option(flags, description) {

  this.flags = flags;

  this.required = flags.indexOf('<') >= 0;

  this.optional = flags.indexOf('[') >= 0;

  this.bool = flags.indexOf('-no-') === -1;

  flags = flags.split(/[ ,|]+/);

  if (flags.length > 1 && !/^[[<]/.test(flags[1])) this.short = flags.shift();

  this.long = flags.shift();

  this.description = description || '';

}

/**

 * Return option name.

 *

 * @return {String}

 * @api private

 */

Option.prototype.name = function() {

  return this.long

    .replace('--', '')

    .replace('no-', '');

};

/**

 * Return option name, in a camelcase format that can be used

 * as a object attribute key.

 *

 * @return {String}

 * @api private

 */

Option.prototype.attributeName = function() {

  return camelcase(this.name());

};

/**

 * Check if `arg` matches the short or long flag.

 *

 * @param {String} arg

 * @return {Boolean}

 * @api private

 */

Option.prototype.is = function(arg) {

  return this.short === arg || this.long === arg;

};

/**

 * Initialize a new `Command`.

 *

 * @param {String} name

 * @api public

 */

function Command(name) {

  this.commands = [];

  this.options = [];

  this._execs = {};

  this._allowUnknownOption = false;

  this._args = [];

  this._name = name || '';

}

/**

 * Add command `name`.

 *

 * The `.action()` callback is invoked when the

 * command `name` is specified via __ARGV__,

 * and the remaining arguments are applied to the

 * function for access.

 *

 * When the `name` is "*" an un-matched command

 * will be passed as the first arg, followed by

 * the rest of __ARGV__ remaining.

 *

 * Examples:

 *

 *      program

 *        .version('0.0.1')

 *        .option('-C, --chdir <path>', 'change the working directory')

 *        .option('-c, --config <path>', 'set config path. defaults to ./deploy.conf')

 *        .option('-T, --no-tests', 'ignore test hook')

 *

 *      program

 *        .command('setup')

 *        .description('run remote setup commands')

 *        .action(function() {

 *          console.log('setup');

 *        });

 *

 *      program

 *        .command('exec <cmd>')

 *        .description('run the given remote command')

 *        .action(function(cmd) {

 *          console.log('exec "%s"', cmd);

 *        });

 *

 *      program

 *        .command('teardown <dir> [otherDirs...]')

 *        .description('run teardown commands')

 *        .action(function(dir, otherDirs) {

 *          console.log('dir "%s"', dir);

 *          if (otherDirs) {

 *            otherDirs.forEach(function (oDir) {

 *              console.log('dir "%s"', oDir);

 *            });

 *          }

 *        });

 *

 *      program

 *        .command('*')

 *        .description('deploy the given env')

 *        .action(function(env) {

 *          console.log('deploying "%s"', env);

 *        });

 *

 *      program.parse(process.argv);

  *

 * @param {String} name

 * @param {String} [desc] for git-style sub-commands

 * @return {Command} the new command

 * @api public

 */

Command.prototype.command = function(name, desc, opts) {

  if (typeof desc === 'object' && desc !== null) {

    opts = desc;

    desc = null;

  }

  opts = opts || {};

  var args = name.split(/ +/);

  var cmd = new Command(args.shift());

  if (desc) {

    cmd.description(desc);

    this.executables = true;

    this._execs[cmd._name] = true;

    if (opts.isDefault) this.defaultExecutable = cmd._name;

  }

  cmd._noHelp = !!opts.noHelp;

  this.commands.push(cmd);

  cmd.parseExpectedArgs(args);

  cmd.parent = this;

  if (desc) return this;

  return cmd;

};

/**

 * Define argument syntax for the top-level command.

 *

 * @api public

 */

Command.prototype.arguments = function(desc) {

  return this.parseExpectedArgs(desc.split(/ +/));

};

/**

 * Add an implicit `help [cmd]` subcommand

 * which invokes `--help` for the given command.

 *

 * @api private

 */

Command.prototype.addImplicitHelpCommand = function() {

  this.command('help [cmd]', 'display help for [cmd]');

};

/**

 * Parse expected `args`.

 *

 * For example `["[type]"]` becomes `[{ required: false, name: 'type' }]`.

 *

 * @param {Array} args

 * @return {Command} for chaining

 * @api public

 */

Command.prototype.parseExpectedArgs = function(args) {

  if (!args.length) return;

  var self = this;

  args.forEach(function(arg) {

    var argDetails = {

      required: false,

      name: '',

      variadic: false

    };

    switch (arg[0]) {

      case '<':

        argDetails.required = true;

        argDetails.name = arg.slice(1, -1);

        break;

      case '[':

        argDetails.name = arg.slice(1, -1);

        break;

    }

    if (argDetails.name.length > 3 && argDetails.name.slice(-3) === '...') {

      argDetails.variadic = true;

      argDetails.name = argDetails.name.slice(0, -3);

    }

    if (argDetails.name) {

      self._args.push(argDetails);

    }

  });

  return this;

};

/**

 * Register callback `fn` for the command.

 *

 * Examples:

 *

 *      program

 *        .command('help')

 *        .description('display verbose help')

 *        .action(function() {

 *           // output help here

 *        });

 *

 * @param {Function} fn

 * @return {Command} for chaining

 * @api public

 */

Command.prototype.action = function(fn) {

  var self = this;

  var listener = function(args, unknown) {

    // Parse any so-far unknown options

    args = args || [];

    unknown = unknown || [];

    var parsed = self.parseOptions(unknown);

    // Output help if necessary

    outputHelpIfNecessary(self, parsed.unknown);

    // If there are still any unknown options, then we simply

    // die, unless someone asked for help, in which case we give it

    // to them, and then we die.

    if (parsed.unknown.length > 0) {

      self.unknownOption(parsed.unknown[0]);

    }

    // Leftover arguments need to be pushed back. Fixes issue #56

    if (parsed.args.length) args = parsed.args.concat(args);

    self._args.forEach(function(arg, i) {

      if (arg.required && args[i] == null) {

        self.missingArgument(arg.name);

      } else if (arg.variadic) {

        if (i !== self._args.length - 1) {

          self.variadicArgNotLast(arg.name);

        }

        args[i] = args.splice(i);

      }

    });

    // Always append ourselves to the end of the arguments,

    // to make sure we match the number of arguments the user

    // expects

    if (self._args.length) {

      args[self._args.length] = self;

    } else {

      args.push(self);

    }

    fn.apply(self, args);

  };

  var parent = this.parent || this;

  var name = parent === this ? '*' : this._name;

  parent.on('command:' + name, listener);

  if (this._alias) parent.on('command:' + this._alias, listener);

  return this;

};

/**

 * Define option with `flags`, `description` and optional

 * coercion `fn`.

 *

 * The `flags` string should contain both the short and long flags,

 * separated by comma, a pipe or space. The following are all valid

 * all will output this way when `--help` is used.

 *

 *    "-p, --pepper"

 *    "-p|--pepper"

 *    "-p --pepper"

 *

 * Examples:

 *

 *     // simple boolean defaulting to false

 *     program.option('-p, --pepper', 'add pepper');

 *

 *     --pepper

 *     program.pepper

 *     // => Boolean

 *

 *     // simple boolean defaulting to true

 *     program.option('-C, --no-cheese', 'remove cheese');

 *

 *     program.cheese

 *     // => true

 *

 *     --no-cheese

 *     program.cheese

 *     // => false

 *

 *     // required argument

 *     program.option('-C, --chdir <path>', 'change the working directory');

 *

 *     --chdir /tmp

 *     program.chdir

 *     // => "/tmp"

 *

 *     // optional argument

 *     program.option('-c, --cheese [type]', 'add cheese [marble]');

 *

 * @param {String} flags

 * @param {String} description

 * @param {Function|*} [fn] or default

 * @param {*} [defaultValue]

 * @return {Command} for chaining

 * @api public

 */

Command.prototype.option = function(flags, description, fn, defaultValue) {

  var self = this,

    option = new Option(flags, description),

    oname = option.name(),

    name = option.attributeName();

  // default as 3rd arg

  if (typeof fn !== 'function') {

    if (fn instanceof RegExp) {

      var regex = fn;

      fn = function(val, def) {

        var m = regex.exec(val);

        return m ? m[0] : def;

      };

    } else {

      defaultValue = fn;

      fn = null;

    }

  }

  // preassign default value only for --no-*, [optional], or <required>

  if (!option.bool || option.optional || option.required) {

    // when --no-* we make sure default is true

    if (!option.bool) defaultValue = true;

    // preassign only if we have a default

    if (defaultValue !== undefined) {

      self[name] = defaultValue;

      option.defaultValue = defaultValue;

    }

  }

  // register the option

  this.options.push(option);

  // when it's passed assign the value

  // and conditionally invoke the callback

  this.on('option:' + oname, function(val) {

    // coercion

    if (val !== null && fn) {

      val = fn(val, self[name] === undefined ? defaultValue : self[name]);

    }

    // unassigned or bool

    if (typeof self[name] === 'boolean' || typeof self[name] === 'undefined') {

      // if no value, bool true, and we have a default, then use it!

      if (val == null) {

        self[name] = option.bool

          ? defaultValue || true

          : false;

      } else {

        self[name] = val;

      }

    } else if (val !== null) {

      // reassign

      self[name] = val;

    }

  });

  return this;

};

/**

 * Allow unknown options on the command line.

 *

 * @param {Boolean} arg if `true` or omitted, no error will be thrown

 * for unknown options.

 * @api public

 */

Command.prototype.allowUnknownOption = function(arg) {

  this._allowUnknownOption = arguments.length === 0 || arg;

  return this;

};

/**

 * Parse `argv`, settings options and invoking commands when defined.

 *

 * @param {Array} argv

 * @return {Command} for chaining

 * @api public

 */

Command.prototype.parse = function(argv) {

  // implicit help

  if (this.executables) this.addImplicitHelpCommand();

  // store raw args

  this.rawArgs = argv;

  // guess name

  this._name = this._name || basename(argv[1], '.js');

  // github-style sub-commands with no sub-command

  if (this.executables && argv.length < 3 && !this.defaultExecutable) {

    // this user needs help

    argv.push('--help');

  }

  // process argv

  var parsed = this.parseOptions(this.normalize(argv.slice(2)));

  var args = this.args = parsed.args;

  var result = this.parseArgs(this.args, parsed.unknown);

  // executable sub-commands

  var name = result.args[0];

  var aliasCommand = null;

  // check alias of sub commands

  if (name) {

    aliasCommand = this.commands.filter(function(command) {

      return command.alias() === name;

    })[0];

  }

  if (this._execs[name] === true) {

    return this.executeSubCommand(argv, args, parsed.unknown);

  } else if (aliasCommand) {

    // is alias of a subCommand

    args[0] = aliasCommand._name;

    return this.executeSubCommand(argv, args, parsed.unknown);

  } else if (this.defaultExecutable) {

    // use the default subcommand

    args.unshift(this.defaultExecutable);

    return this.executeSubCommand(argv, args, parsed.unknown);

  }

  return result;

};

/**

 * Execute a sub-command executable.

 *

 * @param {Array} argv

 * @param {Array} args

 * @param {Array} unknown

 * @api private

 */

Command.prototype.executeSubCommand = function(argv, args, unknown) {

  args = args.concat(unknown);

  if (!args.length) this.help();

  if (args[0] === 'help' && args.length === 1) this.help();

  // <cmd> --help

  if (args[0] === 'help') {

    args[0] = args[1];

    args[1] = '--help';

  }

  // executable

  var f = argv[1];

  // name of the subcommand, link `pm-install`

  var bin = basename(f, path.extname(f)) + '-' + args[0];

  // In case of globally installed, get the base dir where executable

  //  subcommand file should be located at

  var baseDir;

  var resolvedLink = fs.realpathSync(f);

  baseDir = dirname(resolvedLink);

  // prefer local `./<bin>` to bin in the $PATH

  var localBin = path.join(baseDir, bin);

  // whether bin file is a js script with explicit `.js` or `.ts` extension

  var isExplicitJS = false;

  if (exists(localBin + '.js')) {

    bin = localBin + '.js';

    isExplicitJS = true;

  } else if (exists(localBin + '.ts')) {

    bin = localBin + '.ts';

    isExplicitJS = true;

  } else if (exists(localBin)) {

    bin = localBin;

  }

  args = args.slice(1);

  var proc;

  if (process.platform !== 'win32') {

    if (isExplicitJS) {

      args.unshift(bin);

      // add executable arguments to spawn

      args = (process.execArgv || []).concat(args);

      proc = spawn(process.argv[0], args, { stdio: 'inherit', customFds: [0, 1, 2] });

    } else {

      proc = spawn(bin, args, { stdio: 'inherit', customFds: [0, 1, 2] });

    }

  } else {

    args.unshift(bin);

    proc = spawn(process.execPath, args, { stdio: 'inherit' });

  }

  var signals = ['SIGUSR1', 'SIGUSR2', 'SIGTERM', 'SIGINT', 'SIGHUP'];

  signals.forEach(function(signal) {

    process.on(signal, function() {

      if (proc.killed === false && proc.exitCode === null) {

        proc.kill(signal);

      }

    });

  });

  proc.on('close', process.exit.bind(process));

  proc.on('error', function(err) {

    if (err.code === 'ENOENT') {

      console.error('error: %s(1) does not exist, try --help', bin);

    } else if (err.code === 'EACCES') {

      console.error('error: %s(1) not executable. try chmod or run with root', bin);

    }

    process.exit(1);

  });

  // Store the reference to the child process

  this.runningCommand = proc;

};

/**

 * Normalize `args`, splitting joined short flags. For example

 * the arg "-abc" is equivalent to "-a -b -c".

 * This also normalizes equal sign and splits "--abc=def" into "--abc def".

 *

 * @param {Array} args

 * @return {Array}

 * @api private

 */

Command.prototype.normalize = function(args) {

  var ret = [],

    arg,

    lastOpt,

    index;

  for (var i = 0, len = args.length; i < len; ++i) {

    arg = args[i];

    if (i > 0) {

      lastOpt = this.optionFor(args[i - 1]);

    }

    if (arg === '--') {

      // Honor option terminator

      ret = ret.concat(args.slice(i));

      break;

    } else if (lastOpt && lastOpt.required) {

      ret.push(arg);

    } else if (arg.length > 1 && arg[0] === '-' && arg[1] !== '-') {

      arg.slice(1).split('').forEach(function(c) {

        ret.push('-' + c);

      });

    } else if (/^--/.test(arg) && ~(index = arg.indexOf('='))) {

      ret.push(arg.slice(0, index), arg.slice(index + 1));

    } else {

      ret.push(arg);

    }

  }

  return ret;

};

/**

 * Parse command `args`.

 *

 * When listener(s) are available those

 * callbacks are invoked, otherwise the "*"

 * event is emitted and those actions are invoked.

 *

 * @param {Array} args

 * @return {Command} for chaining

 * @api private

 */

Command.prototype.parseArgs = function(args, unknown) {

  var name;

  if (args.length) {

    name = args[0];

    if (this.listeners('command:' + name).length) {

      this.emit('command:' + args.shift(), args, unknown);

    } else {

      this.emit('command:*', args);

    }

  } else {

    outputHelpIfNecessary(this, unknown);

    // If there were no args and we have unknown options,

    // then they are extraneous and we need to error.

    if (unknown.length > 0) {

      this.unknownOption(unknown[0]);

    }

    if (this.commands.length === 0 &&

        this._args.filter(function(a) { return a.required; }).length === 0) {

      this.emit('command:*');

    }

  }

  return this;

};

/**

 * Return an option matching `arg` if any.

 *

 * @param {String} arg

 * @return {Option}

 * @api private

 */

Command.prototype.optionFor = function(arg) {

  for (var i = 0, len = this.options.length; i < len; ++i) {

    if (this.options[i].is(arg)) {

      return this.options[i];

    }

  }

};

/**

 * Parse options from `argv` returning `argv`

 * void of these options.

 *

 * @param {Array} argv

 * @return {Array}

 * @api public

 */

Command.prototype.parseOptions = function(argv) {

  var args = [],

    len = argv.length,

    literal,

    option,

    arg;

  var unknownOptions = [];

  // parse options

  for (var i = 0; i < len; ++i) {

    arg = argv[i];

    // literal args after --

    if (literal) {

      args.push(arg);

      continue;

    }

    if (arg === '--') {

      literal = true;

      continue;

    }

    // find matching Option

    option = this.optionFor(arg);

    // option is defined

    if (option) {

      // requires arg

      if (option.required) {

        arg = argv[++i];

        if (arg == null) return this.optionMissingArgument(option);

        this.emit('option:' + option.name(), arg);

      // optional arg

      } else if (option.optional) {

        arg = argv[i + 1];

        if (arg == null || (arg[0] === '-' && arg !== '-')) {

          arg = null;

        } else {

          ++i;

        }

        this.emit('option:' + option.name(), arg);

      // bool

      } else {

        this.emit('option:' + option.name());

      }

      continue;

    }

    // looks like an option

    if (arg.length > 1 && arg[0] === '-') {

      unknownOptions.push(arg);

      // If the next argument looks like it might be

      // an argument for this option, we pass it on.

      // If it isn't, then it'll simply be ignored

      if ((i + 1) < argv.length && argv[i + 1][0] !== '-') {

        unknownOptions.push(argv[++i]);

      }

      continue;

    }

    // arg

    args.push(arg);

  }

  return { args: args, unknown: unknownOptions };

};

/**

 * Return an object containing options as key-value pairs

 *

 * @return {Object}

 * @api public

 */

Command.prototype.opts = function() {

  var result = {},

    len = this.options.length;

  for (var i = 0; i < len; i++) {

    var key = this.options[i].attributeName();

    result[key] = key === this._versionOptionName ? this._version : this[key];

  }

  return result;

};

/**

 * Argument `name` is missing.

 *

 * @param {String} name

 * @api private

 */

Command.prototype.missingArgument = function(name) {

  console.error("error: missing required argument `%s'", name);

  process.exit(1);

};

/**

 * `Option` is missing an argument, but received `flag` or nothing.

 *

 * @param {String} option

 * @param {String} flag

 * @api private

 */

Command.prototype.optionMissingArgument = function(option, flag) {

  if (flag) {

    console.error("error: option `%s' argument missing, got `%s'", option.flags, flag);

  } else {

    console.error("error: option `%s' argument missing", option.flags);

  }

  process.exit(1);

};

/**

 * Unknown option `flag`.

 *

 * @param {String} flag

 * @api private

 */

Command.prototype.unknownOption = function(flag) {

  if (this._allowUnknownOption) return;

  console.error("error: unknown option `%s'", flag);

  process.exit(1);

};

/**

 * Variadic argument with `name` is not the last argument as required.

 *

 * @param {String} name

 * @api private

 */

Command.prototype.variadicArgNotLast = function(name) {

  console.error("error: variadic arguments must be last `%s'", name);

  process.exit(1);

};

/**

 * Set the program version to `str`.

 *

 * This method auto-registers the "-V, --version" flag

 * which will print the version number when passed.

 *

 * @param {String} str

 * @param {String} [flags]

 * @return {Command} for chaining

 * @api public

 */

Command.prototype.version = function(str, flags) {

  if (arguments.length === 0) return this._version;

  this._version = str;

  flags = flags || '-V, --version';

  var versionOption = new Option(flags, 'output the version number');

  this._versionOptionName = versionOption.long.substr(2) || 'version';

  this.options.push(versionOption);

  this.on('option:' + this._versionOptionName, function() {

    process.stdout.write(str + '\n');

    process.exit(0);

  });

  return this;

};

/**

 * Set the description to `str`.

 *

 * @param {String} str

 * @param {Object} argsDescription

 * @return {String|Command}

 * @api public

 */

Command.prototype.description = function(str, argsDescription) {

  if (arguments.length === 0) return this._description;

  this._description = str;

  this._argsDescription = argsDescription;

  return this;

};

/**

 * Set an alias for the command

 *

 * @param {String} alias

 * @return {String|Command}

 * @api public

 */

Command.prototype.alias = function(alias) {

  var command = this;

  if (this.commands.length !== 0) {

    command = this.commands[this.commands.length - 1];

  }

  if (arguments.length === 0) return command._alias;

  if (alias === command._name) throw new Error('Command alias can\'t be the same as its name');

  command._alias = alias;

  return this;

};

/**

 * Set / get the command usage `str`.

 *

 * @param {String} str

 * @return {String|Command}

 * @api public

 */

Command.prototype.usage = function(str) {

  var args = this._args.map(function(arg) {

    return humanReadableArgName(arg);

  });

  var usage = '[options]' +

    (this.commands.length ? ' [command]' : '') +

    (this._args.length ? ' ' + args.join(' ') : '');

  if (arguments.length === 0) return this._usage || usage;

  this._usage = str;

  return this;

};

/**

 * Get or set the name of the command

 *

 * @param {String} str

 * @return {String|Command}

 * @api public

 */

Command.prototype.name = function(str) {

  if (arguments.length === 0) return this._name;

  this._name = str;

  return this;

};

/**

 * Return prepared commands.

 *

 * @return {Array}

 * @api private

 */

Command.prototype.prepareCommands = function() {

  return this.commands.filter(function(cmd) {

    return !cmd._noHelp;

  }).map(function(cmd) {

    var args = cmd._args.map(function(arg) {

      return humanReadableArgName(arg);

    }).join(' ');

    return [

      cmd._name +

        (cmd._alias ? '|' + cmd._alias : '') +

        (cmd.options.length ? ' [options]' : '') +

        (args ? ' ' + args : ''),

      cmd._description

    ];

  });

};

/**

 * Return the largest command length.

 *

 * @return {Number}

 * @api private

 */

Command.prototype.largestCommandLength = function() {

  var commands = this.prepareCommands();

  return commands.reduce(function(max, command) {

    return Math.max(max, command[0].length);

  }, 0);

};

/**

 * Return the largest option length.

 *

 * @return {Number}

 * @api private

 */

Command.prototype.largestOptionLength = function() {

  var options = [].slice.call(this.options);

  options.push({

    flags: '-h, --help'

  });

  return options.reduce(function(max, option) {

    return Math.max(max, option.flags.length);

  }, 0);

};

/**

 * Return the largest arg length.

 *

 * @return {Number}

 * @api private

 */

Command.prototype.largestArgLength = function() {

  return this._args.reduce(function(max, arg) {

    return Math.max(max, arg.name.length);

  }, 0);

};

/**

 * Return the pad width.

 *

 * @return {Number}

 * @api private

 */

Command.prototype.padWidth = function() {

  var width = this.largestOptionLength();

  if (this._argsDescription && this._args.length) {

    if (this.largestArgLength() > width) {

      width = this.largestArgLength();

    }

  }

  if (this.commands && this.commands.length) {

    if (this.largestCommandLength() > width) {

      width = this.largestCommandLength();

    }

  }

  return width;

};

/**

 * Return help for options.

 *

 * @return {String}

 * @api private

 */

Command.prototype.optionHelp = function() {

  var width = this.padWidth();

  // Append the help information

  return this.options.map(function(option) {

    return pad(option.flags, width) + '  ' + option.description +

      ((option.bool && option.defaultValue !== undefined) ? ' (default: ' + JSON.stringify(option.defaultValue) + ')' : '');

  }).concat([pad('-h, --help', width) + '  ' + 'output usage information'])

    .join('\n');

};

/**

 * Return command help documentation.

 *

 * @return {String}

 * @api private

 */

Command.prototype.commandHelp = function() {

  if (!this.commands.length) return '';

  var commands = this.prepareCommands();

  var width = this.padWidth();

  return [

    'Commands:',

    commands.map(function(cmd) {

      var desc = cmd[1] ? '  ' + cmd[1] : '';

      return (desc ? pad(cmd[0], width) : cmd[0]) + desc;

    }).join('\n').replace(/^/gm, '  '),

    ''

  ].join('\n');

};

/**

 * Return program help documentation.

 *

 * @return {String}

 * @api private

 */

Command.prototype.helpInformation = function() {

  var desc = [];

  if (this._description) {

    desc = [

      this._description,

      ''

    ];

    var argsDescription = this._argsDescription;

    if (argsDescription && this._args.length) {

      var width = this.padWidth();

      desc.push('Arguments:');

      desc.push('');

      this._args.forEach(function(arg) {

        desc.push('  ' + pad(arg.name, width) + '  ' + argsDescription[arg.name]);

      });

      desc.push('');

    }

  }

  var cmdName = this._name;

  if (this._alias) {

    cmdName = cmdName + '|' + this._alias;

  }

  var usage = [

    'Usage: ' + cmdName + ' ' + this.usage(),

    ''

  ];