An excerpt from the US Flag code and a verse from a song by Henry Holcomb Bennett…
…when the flag is passing in a parade or in a review, those not in uniform should remove their headdress with their right hand and hold it at the left shoulder, the hand being over the heart.
A recent change to the code allows any veteran , covered or uncovered, to render a hand salute.
Along the street there comes
A blare of bugles, a ruffle of drums,
A flash of color beneath the sky:
The flag is passing by.