VIM block comment

1. Go to the first line you want to comment, press CtrlV. This will put the editor in the VISUAL BLOCK mode.
2. Then using the arrow key and select until the last line.
3. Now press Shift+I, which will put the editor in INSERT mode and then press #. This will add a hash to the first line.
4. Then press Esc (give it a second), and it will insert a # character on all other selected lines.