miller VS ndjson.github.io

jq and miller[1] are essential parts of my toolbelt, right up there with awk and vim.

[1]: https://github.com/johnkerl/miller

> This works really well if your problem can be solved in one or two liners.

My personal comfort threshold is around the 100-line mark. It's even possible to write maintainable shell scripts up to 500 lines, but it mostly depends on the problem you're trying to solve, and the discipline of the programmer to follow best practices (use sane defaults, ShellCheck, etc.).

> It go bad very quickly when, say, you have two CSV files and want to join them the sql-way.

In that case we're talking about structured data, and, yeah, Perl or Python would be easier to work with. That said, depending on the complexity of the CSV, you can still go a long way with plain Bash with IFS/read(1) or tr(1) to split CSV columns. This wouldn't be very robust, but there are tools that handle CSV specifically[1], which can be composed in a shell script just fine.

So it's always a balancing act of being productive quickly with a shell script, or reaching out for a programming language once the tools aren't a good fit, or maintenance becomes an issue.

[1]: https://miller.readthedocs.io/

where mlr is from https://github.com/johnkerl/miller

if this class of problems (i.e., csv/tsv data) is your main target you may find miller (https://github.com/johnkerl/miller) much more useful in the long run

That said, you may be interested in Miller (https://github.com/johnkerl/miller) which provides similar capabilities for CSV, JSON, and XML files. It doesn't use a SQL grammar, but that's just the proverbial lipstick on the thing. I'm not the author, but I have used it and I see some parallels in use cases at the very least.

worth giving Miller a shot

CSV utilities (still haven't pick a favorite one...): https://github.com/harelba/q https://github.com/BurntSushi/xsv https://github.com/wireservice/csvkit https://github.com/johnkerl/miller

However, since every JSON document can be represented in a single line, something like newline-delimited JSON / JSON Lines feels like it would've been more suitable for that kind of data.

No one uses that format for streamed json, see ndson and jsonl

http://ndjson.org/

The size complaint is overblown, as repeated fields are compressed away.

As other folks rightfully commented, csv is a mine field. One should assume every CSV file is broken in some way. They also don't enumerate any of the downsides of CSV.

What people should consider is using formats like Avro or Parquet that carry their schema with them so the data can be loaded and analyzed without have to manually deal with column meaning.

What is ndjson? Newline delimited JSON is the format the Algolia CLI reads from and writes to files. This means that any command that passes ndjson formatted data as output or accepts it as input can be piped together with an Algolia CLI command! We’ll see more of this in the next example

You might consider using json-lines format (also known as newline-delimited JSON), in which each line is a separate JSON document so they can be loaded individually.

The format you're getting is known as Newline-Delimited JSON. Instead of trying to parse the whole input and pass that to the JSON Decoder, you can use something like bufio.Scanner to get and parse it line by line.

This is in oposition to NDJSON, which allows to split records without deserializing JSON itself, via e.g. read_lines. fwiw CSV suffers from the same problem as JSON - generally not possible to break into records without deserializing. It is worse than NDJSON because the character \n may appear at any position within an item, thus forbidding read_lines.

I've always seen it referred to as ndjson

I think this would be fine, as long as the CSV layer was still parsable using the RFC 4180, then you could still use a normal CSV parser to parse the CSV layer and a normal JSON parser to parse the JSON layer. My worry with your example is that it is nether format, so it will need custom serialisation and deserialisation logic as it is essentially a bran new format.

https://datatracker.ietf.org/doc/html/rfc4180

If you’re looking for line-oriented JSON, another option would be ndjson: http://ndjson.org/