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, and Call of Duty: Modern Warfare 2. 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. Before Call of Duty 4: Modern Warfare the most common melee attack was the butt of the weapon. The knife is triggered by pressing the melee 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 enemy players (except Zombies), even those using 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(the Commando perk will increase it slightly). 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 if the target is far away enough, but if the target is close a slash will be used instead, the slash has a greater chance of hitting as it has a wider range, and in lag filled online matches the lunge misses occasionally.

In Call of Duty 4: Modern Warfare 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 Backstabb.

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.

The Tactical Knife is a weapon attachment in Call of Duty: Modern Warfare 2 that allows players to kill someone with their knife approximately twice as fast. Pistols are the only weapons compatible with the tactical knife, the .44 Magnum being the favorite because the gun itself unlocked early and it's easier to rack up the 100 kills required to obtain the knife. The wide slash of the standard combat knife isn't present when using a tactical knife, but the window in which the opponent may be lunged seems widened. The lunge is also far faster with the tactical knife; players often enter matches with intent on using only their melee attack for sheer amusement when using it.

When in third person mode, if you use knife attack in prone it looks like you swing your gun at the enemy, if you look your knife actually sticks out of your gun, like a bayonet which as been put on wrong. This is a glitch as it happened when you are in prone on COD4 too. Try it with an M9, and it actually looks like the knife is bigger than the gun.

It is possible to dodge a knife lunge, leaving the knifer defenseless for a short while, though this is only generally possibly while using Lightweight and a light weapon such as an SMG.

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 Knife, and the knife used in Call of Duty: World at War is the Kabar USMC Fighting Knife. The knife used in Call of Duty: Modern Warfare 2 appears to be a Blackhawk Tatang.


 * 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. This technique, usually used with a large-bodied flash light, is called the "Harries " technique named after proponent Michael Harries. Since the advent of smaller flash lights, this technique is considered outdated for use with them, because of the lack of recoil control with the second hand. It still sometimes taught for use with knives.


 * 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 piece of equipment, having its own crosshair and taking up a primary grenade slot. The knife can be retrieved after being thrown, for an unlimited amount of uses. The throwing knife appears to be smaller than the standard melee knife.


 * 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. Using a knife for this glitch is generally inadvisable as the recovery time of a slash will often be longer than waiting out the reload. Double-tapping the "switch weapons" button is most effective for this glitch, with a short sprint coming in at a close second..


 * 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 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.


 * In Call of Duty: Modern Warfare 2, NPC's now have the ability to use the knife, although it is extremely rare. Allied NPCs will usually throw enemy NPCs onto the floor and shoot them upon close contact instead of using the knife.


 * In Call of Duty: Modern Warfare 2, in the level "Endgame", after the helicopter crash, your knife will become very dull and worn.
 * In Third Person Tactical of Modern Warfare 2, there is no knife animation when prone. Instead, you use the butt of your gun. This might be a mistake on Infinity Ward's part because the melee animation in first person while prone is still involves a knife.
 * The Bayonet attachment in Call of Duty: World at War increases the range of your knife the same distance that Commando in Call of Duty: Modern Warfare 2 does. However, in, the bayonet slows down the speed of your knife.

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