Knife

The knife is the standard close quarters combat melee weapon in Call of Duty 4: Modern Warfare and one of the melee weapons in Call of Duty: World at War. Prior to Call of Duty 4: Modern Warfare, the knife was not a commonly used melee weapon in previous singleplayer Call of Duty games; it was available only in missions that feature stealth and/or reconnaissance. The knife is triggered by pressing the use button (V on the PC, clicking the right thumbstick on the Xbox 360, or clicking the R3 Button on the PS3), as taught in the F.N.G. mission. However, on the Wii it is triggered by shaking the controller or by pressing down on the d-pad.

Multiplayer
The knife will always kill an enemy player (even with the Juggernaut perk) in one stab/slash (provided the knife hits the enemy). In Old School multiplayer matches, however, two knife attacks are required to kill an enemy player at full health. The knife is only effective at extremely close range. Using the knife to kill an enemy player will not reveal the player's position on the minimap, allowing the player to perform stealth kills without need of a suppressor. The knife will make a rather thick slash or stab sound, and will sometimes shed blood. When stabbing in multiplayer, the player will lunge at the target (similar to a melee attack in Halo).

In Call of Duty 4 multiplayer, the knife has a number of challenges that will reward a player XP for using the knife in certain ways. These challenges include | Knife Veteran, | Slasher and | Backstabber.

Typically, there are two ways to how knives are used: point blank stab or slash triggered by the use key when standing still, or a lunge against an enemy player (walking towards the player or stationary) triggered pressing the use key while moving. Experienced players will use the knife when out of ammo and indoors, but will switch out an empty weapon for a new one at the first chance. In Hardcore modes, the knife is next to useless because most weapons perform one-hit kills, especially at close range.

Trivia

 * In singleplayer, enemies don't use the knife unless scripted to do so. Instead, they will bash the player with the stock of the weapon they are currently holding.


 * In Shi No Numa if you need reviving and you're in the water somewhere (this works in the comm room), you can use your knife and your player will jump out of the water.


 * The knife used in Call of Duty 4: Modern Warfare appears to be a SOG Bowie, and the knife used in Call of Duty: World at War is the Kabar USMC Fighting Knife.


 * If grenades or the knife or both are used exclusively in any of the Campaign levels of Call of Duty: World at War on Normal difficulty or higher, an achievement or trophy can be earned called "Kamikaze". It is worth 15 GS on the Xbox 360 or a Silver Trophy on the PS3. The bayonet can be used in place of the knife, though, so it is frequently used for its longer reach.


 * You can only stab on the Wii version if aim assist is activated.


 * In Call of Duty: Modern Warfare 2, the weapon attachment, Tactical Knife, will allow the knife to be held when using the pistol, to allow a faster slash. The hand holding the knife will still be used to support the pistol, a bit like Naked Snake in Metal Gear Solid 3. This sort of technique is already taught in military and police training, though with a flashlight propping the pistol instead.


 * In Call of Duty: Modern Warfare 2, it has been shown that a new knife called the throwing knife can be thrown at enemy players. It is treated as a grenade, having its own crosshair and taking up a primary grenade slot. The knife can be retrived after being thrown, for an unlimited amount of uses. The throwing knife appears to be smaller than the standard melee knife, so use of the normal knife is most likely enabled after having used the throwng knife and before retrieving it.


 * In the Call of Duty series it is possible to speed up reloading by using the knife, double-tapping the "switch weapons" button, or sprinting slightly while reloading once your magazine fills as opposed to waiting for the reload animation to finish. This technique is known as the Reload Cancel.


 * In Call of Duty 4: Modern Warfare, the G3 with a Silencer has an erroneously long Melee Charge Delay. The knife damage will only register 1.3 seconds after the players hits the knife button. This is a glitch caused by a typo in the game code.


 * In the new Nazi Zombies map Der Riese, players are able to obtain a stronger version of the knife called the Bowie knife.


 * If you knife someone at point blank range you will slash them, however, if you are any farther than that you will perform a stabbing animation.


 * In the Nintendo DS versions of the games there is no slash animation - only a stab animation.