function pgsh(ev) {
  var self = this

  ev.on('cmd_entered', function(input) {
    // First word is the command, all others are arguments.
    var parts = input.trim().split(' ')
    var command = self.active ? self.active : parts.splice(0, 1).toString()
    var args = parts
    if (command in self.commands) {
      self[command](args)
    } else if (command) {
      show(command + ' not found')
    }
  })

  var show = function(text) { ev.trigger('disp_add', text) }
  var set = function(text) { ev.trigger('disp_set', text) }

  this.prompt = '<span style="color:blueviolet">pgs </span>' +
    '<span style="color:green">$ </span>'
  this.prompt_su = '<span style="color:tomato">root </span>' +
    '<span style="color:red">% </span>'
  this.welcome = 'Linux parsleygardens.net 3.4.5-6-7-i286 #8 PGS Vimputer ' +
    '3.4.56-7 i286\n\n' +
    '~ Welcome to Parsley Gardens! ~\n' +
    '"He maketh me to lie down in green pa..."\n\n' +
    'Type `help` for list of commands\n\n'
  this.commands = {
    'about': 'Author Information',
    'clear': 'Clears the screen',
    'version': 'Shell Information',
    'git': 'Link to Code Repository',
    'hello': 'Say hello to the computer\nUsage: hello [name]',
    'magic': 'Link to Artist',
    'su': 'Gain Phenomenal Cosmic Power',
    'exit': 'Leave the current context',
    'search': 'Search the Web (with a Duck)\nUsage: search [query]',
    'questions': 'Answer some questions!',
    'help': 'List commands or view information for one\nUsage: help [command]'
  }

  /**
   * The Commands
   */
  this.about = function(args) {
    show('Site by Weiyi Lou ' + new Date().getFullYear() + '\n')
  }
  this.clear = function(args) {
    ev.trigger('disp_clear')
  }
  this.version = function(args) {
    show('Parsley Gardens Shell (pgsh) 1.0.0 Built with ' +
         '<a target="_blank" href="http://riotjs.com/">Riot</a>')
  }
  this.git = function(args) {
    show('Code Repository at <a target="_blank" ' +
         'href="https://code.parsleygardens.net/explore/projects">' +
    'code.parsleygardens.net</a>')
  }
  this.hello = function(args) {
    address = args.join(' ').trim()
    if (address.length == 0) {
      show('Hello to you too')
    } else if (address == 'pgsh') {
      show('Hello human')
    } else {
      show('My name is not "' + address + '"')
    }
  }
  this.magic = function(args) {
    show('Animation and Illustration at <a target="_blank" ' +
         'href="http://slightlymagic.com.au">slightlymagic.com.au</a>')
  }
  this.su = function(args) {
    if (self.su !== true) {
      self.su = true
      if (!self.su_warned) {
        self.su_warned = true
        show('We trust you have received the usual lecture from the ' +
             'local System Administrator.\n' +
             'It usually boils down to these three things:\n\n' +
             '    #1) Respect the privacy of others.\n' +
             '    #2) Think before you type.\n' +
             '    #3) With great power comes great\n\n')
      }
      ev.trigger('prompt_set', self.prompt_su)
    }
  }
  this.exit = function(args) {
    if (self.su) {
      self.su = false
      ev.trigger('prompt_set', self.prompt)
      return
    }
    show('Close browser window to exit')
  }
  this.search = function(args) {
    if (!args.join(' ').trim()) { return show(self.commands.search) }
    ev.trigger('prompt_hide')
    show('Searching for "' + args.join(' ') + '" in new window...')
    setTimeout(function() {
      window.open('https://duckduckgo.com/?q=' + args.join('+'), '_blank')
      ev.trigger('prompt_show')
    }, 1000)
  }
  this.questions = function(args) {
    if (!self.active) {
      self.active = 'questions'
      ev.trigger('context_swap', 'questions')
      set('Welcome to the questions. Do you want to continue?')
      return
    }
    if (args == 'exit') {
      self.active = ''
      ev.trigger('context_swap')
      show('Thanks for answering questions!')
      return
    }
    var questions = [
      'Isn\'t <a href="https://www.youtube.com/watch?v=dQw4w9WgXcQ"' +
      ' target="_blank">this song</a> the best?',
      '1 + 2 = ?',
      'Am I a sandwich?',
      'Where were you at 3:15am on April 14th?',
      "Don't you mean prism?",
      'Butts twelve by pies?',
      'I say there, Monstrosity. Do you know the times?',
      '...is essay-writing an exercise in masking ignorance?',
      'What is the name of the spaces between the teeth of a comb?',
      'Why are you dressed up like Ship\'s Captain?'
    ]
    set('You answered with "' + args + '"!\nNext question!\n' +
      '<span style="color:#555">(Type "exit" to end)</span>\n\n')
    var rand = Math.floor(Math.random() * questions.length);
    show(questions[rand])
  }
  this.help = function(args) {
    command = args.join(' ').trim()
    if (command in self.commands) {
      show(self.commands[command])
    } else if (command) {
      show('No information for: ' + command)
    } else {
      var commands = [];
      for(var name in self.commands) {
        commands.push(name)
      }
      show('Available commands:\n' + commands.sort().join(' ') +
           '\n\n`help [command]` for more information.')
    }
  }
}