A hasty fighting position is the initial stage in the development of a foxhole. It consists whatever objects, such as dirt or logs, can be used to provide cover. As the name implies it can be set up quickly with little effort, but provides a minimum of protection.
Foxholes can be as simple as a literal hole dug into the ground to elaborate structures that can house several troops along with machine guns such as the M-60, or mortarss. These larger structures are often constructed using timber and earth moving equipment by Combat Engineers. They are often used for battalion defence and form pivot points in interlocking fields of fire. They differ from bunkers in that they are part of the firing line rather than behind it and are not as hardened against artillery fire.
The United States Army has elaborate field manuals for the proper construction of foxholes in stages. Each stage develops the fighting position, gradually increasing its effectiveness, while always maintaining functionality. In this way a soldier can improve the position over time, while being able to stop at any time and use the position in a fight.
The term derives from the defensive holes dug by foxes.
The fighting forces of other nations use different terms for much the same thing: in the ANZAC forces, for example, it is a fighting pit.