This comes up every so often. I think there are good reasons it hasn't caught on. Here's a relevant comment from ten years ago:

> whole point is to be roughly human-readable and using non-printing characters defeats that. You can't even easily enter these things via the command line.

> If we're abandoning human-readability, why even bother with ASCII? Just use a binary format. Has anyone actually used ASCII unit and record separator delimiters successfully? I'd be curious about what advantages they had over a binary format, even just a protobuf or Thrift serialized form. If we want to preserve schemalessness, there's stuff like Sereal.

--- arjie, June 8, 2016

https://news.ycombinator.com/item?id=11862769

Here's another one from more than twelve years ago:

> I've done this.

> Everybody hated it. Most text editors don't display anything useful with these characters (either hiding them altogether or showing a useless "uknown" placeholder), and spreadhseet tools don't support the record separator (although they all let you provide a custom entry separator so the "unit" separator can work). Besides the obvious problem that there's no easy way to type the darned things when somebody hand-edits the file.

--- Pxtl, March 26, 2014

https://news.ycombinator.com/item?id=7474600

Yahoo access logs used control characters to separate fields beyond a fixed width field, but it wasn't the record separators. It used ctrl-E to separate fields, which had a one character identifier. Some of the fields had sub-fields which were separated ctrl-F.

Slide 22 https://www.radwin.org/michael/talks/yapache-oscon2006.pdf