class Lt
  def self.ls
    system("ls")
  end

  def self.cd
    puts "this function is currently not operational"
    dir = gets
    system("cd "+dir)
  end

  def self.cat
    puts "please enter the filename"
    file = gets
    system("cat "+file)
  end

  def self.chmod
    puts "Please enter the mode and the file/directory name(777 /some/directory)"
    file = gets

    system("chmod "+mode+" "+file)
  end

  def self.cp
    puts "please enter the source and destination"
    file = gets
    system("cp "+file)
  end

  def self.date
    system("date")
  end

  def self.df
    system("df -h")
  end

  def self.du
    puts "Enter the path"
    path=gets
    system("du -h "+path)
  end

  def self.kill
    system("ps -e")
    puts "Enter the process id to kill"
    pid=gets
    system("kill "+pid)    
  end

  def self.mkdir
    puts"enter the path"
    mdir=gets
    system("mkdir "+mdir)
  end

  def self.mv
    puts"move from source to destination"
    sdir=gets
    ddir=gets
    system("mv "+sdir+" "+ddir)
  end

  def self.passwd
    system("passwd "+gets)
  end
  def self.ps
    system("ps ")
  end

  def self.pwd
    system("pwd")
  end

  def self.rm
    system("rm "+gets)
  end

  def self.rmdir
    system("rmdir "+gets)
  end

  def self.who
    system("who")
  end

  def self.whoami
    system("whoami")
  end
end