Knife

Knives can be found in every Fallout game. Other than this basic variant, other available knives are Combat Knife and Throwing Knife.

Fallout and Fallout 2
A sharp-bladed cutting and stabbing weapon.

Fallout Tactics
A sharp-bladed cutting and stabbing weapon.

Fallout 3
The Knife is a Melee weapon in Fallout 3 and is affected by the Melee Damage Bonus from Strength.

A unique knife, the Ant's Sting, can be obtained through the quest The Superhuman Gambit in Canterbury Commons.

Locations
Knives can be found on random Wastelanders or Raiders, in kitchens, hospitals and many other places across the Wastelands.

A large number of combat knives are found inside the Regulator HQ. You must have the Lawbringer perk to gain entrance.

One can be found when you leave the vault go to silvers house must steal it