jq

A lightweight and flexible command-line JSON processor.

Description

jq is a lightweight and flexible command-line JSON processor. It is used to parse, filter, and transform JSON data. It applies filters to its JSON input and produces results as JSON on standard output.

The simplest filter is ., which copies the input to the output without modification (formatting it nicely).

jq currently supports 64-bit double-precision floating-point numbers (IEEE754).

Installation

For Debian/Ubuntu:

sudo apt-get install jq

For RedHat/CentOS:

sudo yum install jq

Syntax

jq [options] <jq filter> [file...]
jq [options] --args <jq filter> [strings...]

Options

-c               Compact output (one line per object).
-n               Use `null` as the single input value.
-e               Set exit status based on the output.
-s               Slurp: Read all inputs into an array before applying the filter.
-r               Output raw strings instead of JSON texts.
-R               Read raw strings instead of JSON.
-C               Enable colorized output.
-M               Monochrome (no colors).
-S               Sort object keys alphabetically.
--tab            Use tabs for indentation.
--arg k v        Set variable $k to value v.

Examples

Pretty print JSON:

echo '{ "foo": { "bar": { "baz": 123 } } }' | jq '.'

Get a value by key:

echo '{"foo": 42}' | jq '.foo'
# Output: 42

Array operations:

echo '[{"name":"JSON"}, {"name":"XML"}]' | jq '.[1]'

Construct new objects:

echo '{"user":"root","titles":["admin", "super"]}' | jq '{user, role: .titles[]}'

Calculate length:

echo '[1, 2, 3]' | jq 'length'
# Output: 3

Pipe filters:

echo '[{"name":"JSON"}, {"name":"XML"}]' | jq '.[] | .name'

Select items based on condition:

echo '[1, 5, 3, 0, 7]' | jq 'map(select(. >= 5))'
# Output: [5, 7]

String interpolation:

echo '42' | jq '"The input was \(.)"'