function pgsh() {
  this.prompt = '<span style="color:purple">pgs </span><span style="color:green">$ </span>'
  this.welcome = ''
  this.commands = {
    'about': {
      'help': 'Author Information\nUsage: about',
      'run': function(args) {
        if (args.length > 0) { return this.help }
        return 'Site by Weiyi Lou ' + new Date().getFullYear()
      }
    },
    'clear': {
      'help': 'Clears the screen\nUsage: clear',
      'run' : function() { return 'clear' }
    },
    'version': {
      'help': 'Shell Information\nUsage: version',
      'run': function(args) {
        if (args.length > 0) { return this.help }
        return 'Parsley Gardens Shell (pgsh) 1.0.0. Built with <a target="_blank" href="http://riotjs.com/">Riot.js</a>'
      }
    },
    'git': {
      'help': 'Link to Code Repository\nUsage: git',
      'run': function(args) {
        if (args.length > 0) { return this.help }
        return 'Self-Hosted Code Repository at <a target="_blank" href="https://code.parsleygardens.net/explore/projects">code.parsleygardens.net</a>'
      }
    },
    'hello': {
      'help': 'Usage: hello [name]',
      'run': function(args) {
        address = args.join(' ').trim()
        if (address.length == 0) {
          return 'Hello to you too'
        } else if (address == 'pgsh') {
          return 'Hello human'
        } else {
          return 'My name is not "' + address + '"'
        }
      }
    },
    'magic': {
      'help': 'Link to Artist\nUsage: magic',
      'run': function(args) {
        if (args.length > 0) { return this.help }
        return 'Animation and Illustration at <a target="_blank" href="http://slightlymagic.com.au">slightlymagic.com.au</a>'
      }
    },
    'su': {
      'help': 'Substitute as root user for Phenomenal Cosmic Power\nUsage: su',
      'run': function(args, context) {
        if (args.length > 0) { return this.help }
        var output = ''
        if (!context.su) {
          context.oldprompt = context.prompt
          context.prompt = '<span style="color:purple">root </span><span style="color:red">% </span>'
          context.su = true
          output = 'With Great Power comes Great'
        }
        return output
      }
    },
    'exit': {
      'help': 'Usage: exit',
      'run': function(args, context) {
        if (args.length > 0) { return this.help }
        var output = 'Close browser window to exit'
        if (context.su) {
          context.prompt = context.oldprompt
          context.su = false
          output = ''
        }
        return output
      }
    },
    'help': {
      'help': 'List all commands or view information for a command\nUsage: help [command]',
      'run': function(args, context) {
        command = args.join(' ').trim()
        if (command in context.commands) {
          return context.commands[command].help
        } else {
          var output = (command) ? 'Command not found: ' + command + '\n' : ''
          var commands = [];
          for(var name in context.commands) {
            if (name !== 'Parent') { commands.push(name) }
          }
          output += 'Available commands:\n' + commands.sort().join(' ')
          return output
        }
      }
    }
  }
  this.process = function(input) {
    var parts = input.trim().split(' ')
    // First word is the command, all others are arguments.
    var command = parts.splice(0, 1)
    var args = parts
    var output = ''
    if (command in this.commands) {
      var shell = this
      output += this.commands[command].run(args, shell)
    }
    return output
  }
}