1. Method One
    1. Select the layer
    2. Select the brush tool (press B)
    3. Optional - Press & Hold Ctrl(cmd) + Press & Hold Shift + Press N or select New layer
    4. Set Brush panel
    5. Draw Straight Line
      1. Click any where you want
      2. Second click with press & hold Shift Key
      3. Continuously you can do this with press & hold Shift Key
  2. Method Two (Rigid)
    1. Select the layer
    2. Select the pen tool (press P)
    3. Optional - Press & Hold Ctrl(cmd) + Press & Hold Shift + Press N or select New layer
    4. Draw Straight Line
      1. Click any where you want
      2. Second click with press & hold Shift Key
      3. Right click and select stroke path
      4. Select Brush/pencil and OK
      5. Enter