function submit () {
    let commandTokens = input.value.split(' ').filter(e => e !== '')
    console.log('Submitted: ' + commandTokens)
    if (!initialized) {
      theArray = commandTokens.slice(0)
      input.value = ''
      initialized = true
      output.value += theArray.join(' ') + '\n'
      return
    }
    try {
      commands[commandTokens[0]](commandTokens.slice(1))
    } catch (err) {
      output.value += 'Error: invalid command' + '\n'
    } finally {
      input.value = ''
    }
  }