Linear Infighting Neuro-Override Engagement or L.I.N.E. was the US Marine's Hand-to-Hand Combat System from 1989 to 2002, until it was replaced by the Marine Corps Martial Arts Program. It was taught to US Army Special Forces Units from 1998 to 2007.

Created by Ron Donvito, this Close Quarters Combat system is in the public domain as the US Marine Corps Close Quarters Combat Manual. The Shadow Warrior L.I.N.E. Combative Manual contains the original USMC CQC Manual & analysis by Ron Collins a former US Army Hand-to-Hand Combat Instructor awarded for the supplemental information he added to Modern Army Combatives generation one, that are similar to the material found in Gen II MACP, though Mr. Collins denies any credit to this similarity.

This LINE manual is suggested study for all American Homeguard Hand-to-Hand Combat/Self-Defense Combatives certified Instructors in the American Homeguard Survival Academy.