Single File
 

I normally say “caminar de a uno” for “to walk in single file.” However, in the dictionary, I see the term “caminar en fila india.”

Is “en fila india” used universally or does it have a slightly pejorative connotation in some countries?

I understand the history and origin of the term, but I don't want to use it if it has even a hint of disrespect to any indigenous population.

Any input and/or clarification is appreciated.

I don't believe the expression to be derogatory. The English equivalent (Indian file) isn't considered pejorative, but only seems outdated to me. I believe the Spanish expression to be commonly used.
If you'd rather use another phrase, you can say:
en fila
en línea
uno detrás del otro
uno tras otro

Thanks for your reply, Rusty.