"Platoon will fix bayonets! Fix … bayonets!"
"Riflemen! Swords … on!"… because the Light Infantry always have to do it differently…
Basic Information
The bayonet is a piercing weapon, with or without a cutting edge that attaches to the muzzle of a firearm to improve its characteristics as a melee weapon. Historically bayonets have run the gamut from short, ineffectual spikes permanently attached to the weapon by a hinge to detachable sword like objects several feet long. They have been fitted to almost all varieties of long arms at one time or another, also to submachineguns and carbines (which not everyone classes as long arms) and in a few, less sane, cases to pistols and light machine guns.
The modern consensus seems to be for a detachable, bladed item that clips onto the muzzle-brake of the rifle1 and doubles as a utility knife when undogged.
The bayonet originated in a desire to allow musket armed infantry to protect themselves from cavalry attack without the support of a pike phalanx or the additional weight of a swine feather. The first bayonets fitted into the muzzle of the weapon like a plug and tended to interfere with loading (and firing) … not to mention leading to bizzare design features and damaging the bore. Alternative designs seem to have taken a worryingly long time to see the light, but once they did, the plug bayonet was history.
Since its invention, the bayonet seems to have been a primarily defensive weapon - despite being much fetishised by various armies over the years there are relatively few examples of soldiers charging a good order enemy unit with the bayonet and even fewer of such a charge being sucessful. Exceptions are generally found in small unit actions where the attackers considered they signifcantly outclassed their opponents or, alternatively, were desperate to some degree.
The bayonet also seems to be a purely military weapon - governments always seem to react badly to bayonets on privately owned weapons (even antiques) … probably an atavistic recollection of the days in which they could only suppress dissent by sending cavalry to trample the dissenters.
Sources
Wikipedia on bayonets
Some guy that seems to //really// like bayonets