• M-: - Evaluate Emacs Lisp expression
• M-; - Comment line / block
• C-_ - Undo
• ESC-< - Top of the file
• ESC-> - Bottom of the file

Window management

• C-x 5 2 - Create new frame
• C-x 5 0 - Close current frame
• C-x 2 - Vertical frame split
• C-x 3 - Horizontal frame split
• C-x o - Move to other window

Dired

• d - Mark file to deletion
• x - Execute marked changes (e.g. delete marked files)
• g - Refresh