in Indian file

in Indian file

In a line one person or one thing in width; in single file. (Potentially offensive due to the politically incorrect reference to Native Americans.) The students lined up and marched in Indian file toward the auditorium.
See also: file, Indian
References in classic literature ?
So they entered the yard in Indian file, like a tramp and his wife.
Between the two ran the irregular track, so narrow in places that they had to travel in Indian file, and so rough that only practised riders could have traversed it at all.