Convert sequence of JSON lines (JSONL) to JSON array

Question

I have a file where each line is a JSON object. I'd like to convert the file to a JSON array.

The file looks something like this:

{"address":"[email protected]", "topic":"Some topic."}
{"address":"[email protected]", "topic":"Another topic."}
{"address":"[email protected]", "topic":"Yet another topic."}

I'm using bash and jq.

I tried

jq --slurp --raw-input 'split("\n")[:-1]' my_file

But that just treats each line as a string creating a JSON array of strings.

[
  "{\"address\":\"[email protected]\", \"topic\":\"Some topic.\"}",
  "{\"address\":\"[email protected]\", \"topic\":\"Another topic.\"}",
  "{\"address\":\"[email protected]\", \"topic\":\"Yet another topic.\"}"
]

I'd like to have:

[
  {"address":"[email protected]", "topic":"Some topic."},
  {"address":"[email protected]", "topic":"Another topic."},
  {"address":"[email protected]", "topic":"Yet another topic."}
]

How about just jq --slurp < my_file

borrible
– borrible

2020-03-11 14:10:20 +00:00
Commented Mar 11, 2020 at 14:10 — borrible
– borrible, Commented Mar 11, 2020 at 14:10

Charles Duffy · Accepted Answer · 2020-03-11 15:18:41Z

12

jq -n '[inputs]' <in.jsonl >out.json

...or, as suggested by @borrible:

jq --slurp . <in.jsonl >out.json

answered Mar 11, 2020 at 15:18

Charles Duffy

299k43 gold badges441 silver badges497 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

peak · Accepted Answer · 2020-03-11 17:31:11Z

4

For the task at hand, using jq's "slurp" option or [inputs] entails a potentially huge waste of resources.

A trivial but efficient solution can be implemented in awk as follows:

awk 'BEGIN {print "[";} NF==0{next;} n=="" {print;n++;next;} {print ","; print;} END {print "]"}'

An equivalent efficient solution in jq is possible using foreach and inputs, and is left as an exercise.

answered Mar 11, 2020 at 17:31

peak

119k21 gold badges185 silver badges218 bronze badges

1 Comment

Ciro Santilli OurBigBook.com Jun 3 at 7:03

Note that sed golfs way better here! :-) stackoverflow.com/a/79650764/895245

Ciro Santilli OurBigBook.com · Accepted Answer · 2025-06-03 07:02:34Z

0

Alternatively with sed:

echo [; sed '$!s/$/,/' input.jsonl; echo ]

or from stdin:

cat input.jsonl | ( echo [; sed '$!s/$/,/'; echo ] )

Here the $! in sed operates on all line except the last one: sed line range, all but the last line

answered Jun 3 at 7:02

Ciro Santilli OurBigBook.com

392k120 gold badges1.3k silver badges1.1k bronze badges

Collectives™ on Stack Overflow

Convert sequence of JSON lines (JSONL) to JSON array

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related