[atom-editor] Commenting out code blocks in Atom

with all my respect with the comments above, no need to use a package :

1) click on Atom 
1.2) then ATL => the menu bar appear 
1.3) File > Settings  => settings appear
1.4) Keybindings > Search keybinding input => fill "comment"
1.5) you will see :

keybindings panel in atom editor

if you want to change the configuration, you just have to parameter your keymap file