Is the Hadith, "Foot to foot and shoulder to shoulder, the row is straight," authentic, and what is the correct way to apply the description "foot to foot"?

We do not know of a hadith with the exact wording mentioned, but there are hadiths regarding the straightening of rows, among them the hadith of Nu'man ibn Bashir, that the Messenger of Allah, peace and blessings be upon him, said: "Straighten your rows" – three times – "By Allah, you will straighten your rows, or Allah will cause dissension between your hearts." The straightening of the row is achieved by shoulder touching shoulder, foot touching foot, and ankle touching ankle, with the worshipers standing in a straight line without anyone being ahead or behind, and without any gaps. Exaggeration and going to extremes in sticking the feet together is not required; it is sufficient for the feet to be close together, and alignment should be at the heels, not the tips of the toes.