Commenting block of code in VIM

  1. Ctrl + v : Visual block

  2. Select first column of the block of code to comment

  3. Shift + I : moves cursor to beginning and enters insert mode

  4. Type the character which comments the line: # for python or // for c/c++

  5. ESC

To uncomment use visual block (Ctrl + v) to select the commenting characters and delete them by typing x.