I've seen this in some movies and video games about world war 2. Basically whenever a ranking officer wanted to signal his troops to suppress an enemy position, he would sort of punch 2-3 times in forward direction. Could someone help me identify what this signal meant.
In World War 2, US troops almost never used standardized hand signals. That was an invention of the Vietnam War, and even then was primarily used by Rangers and special forces, not everyday soldiers.
Various modern movies, notably "Band of Brothers" and "Saving Private Ryan", anacronistically show actors using hand signals. If you watch contemporary war movies, like "Sands of Iwo Jima" or "Objective: Burma", you will see no hand signals, except maybe a hand wave beckoning ("come forward").
The British used hand signals occasionally and their double time signal, fist up and down, was widely copied by American on the western front.
Beg to differ with answers and comments regarding the US Army's lack of standardized hand signals in the World War II period; it most certainly did have hand signals and they were taught in basic infantry training. Hand signals did not originate with the Viet Nam war. Movies such as “Band of Brothers” and “Saving Private Ryan” were not anachronistic at all in their depictions of troops using hand signals in the field. Of course, whether or not the directors and the folks who trained the actors actually knew they had it right is another question, you would have to ask them, but there is always the possibility that some one really did know what they were doing. Unless said signals were simply made up on the spot, in which case they could well be contrary to how the real soldiers would have been trained.
See FM 22-5 Basic Field Manual -Infantry Drill Regulations, 4 August 1941 with revisions through 1943. Easy download from here: https://archive.org/details/FM22-51941/mode/2up
Once you get past the first 82 pages, the revisions 1941 through 1943 (including some revisions to hand signals which start on page 79), and get to the actual 4 August 1941 manual, one finds Chapter 11 – Signals, where is found Section III - General arm and hand signals. In a visit there, I think, anyone with a nodding acquaintance with US Army hand signals from, oh, say, the Viet Nam era forward will find them familiar even with illustrations showing soldiers sporting the M1917A1 helmet.
Digging a little farther . . .
Likewise the 1939 Infantry Drill Regulations also addresses arm-and-hand signals; see Chapter 11 – Signals. See http://www.easy39th.com/files/FM_22-5_Infantry_Drill_Regulations_1939.pdf
The 1932 Tentative Infantry Drill Regulations has included in Chapter 16 (Drill and combat signals) sections III through VI covering arm-and-hand signals. These sections show pretty much the same as the 1941 regulations except the illustrations show campaign hat head gear as opposed to the M1917A1 helmet.
The 1911 Infantry Drill Regulations describes specific prescribed arm signals in the section entitled "Orders, Commands and Signals" found in Part I of the manual. Arm signals start on page 18, alas without illustration. While not as encompassing as later versions, they do, however, certainly sound familiar, for example:
*“. . . Forward, march. Carry the hand to the shoulder; straighten and hold the arm horizontally, thrusting it in direction of march.
“This signal is also used to execute quick time from double time.
“Halt. Carry the hand to the shoulder; thrust the hand upward and hold the arm vertically.
“Double time, march. Carry the hand to the shoulder; rapidly thrust the hand upward the full extent of the arm several times. . . .”*