jq Command

JSON Query command for filtering data out of a JSON Object, file, or URL. jq is a query language built specifically for interacting with JSON type data. More information can be found at https://jmespath.org/ as well as an online version to test your query Pass or pipe the text to process or a filename

Using jq with a file

# basic.json
   "a": {
      "b": {
         "c": {
            "d": "value"
         }
      }
   },
   "dan": [1,2,3,4,5,6,7,8],
   "ban": "bar",
   "cat": "baz"
}

> jq "basic.json" "a"
=> "a": {
      "b": {
         "c": {
            "d": "value"
         }
      }
   }

> jq "basic.json" "a.b.c.d"
=> value

> jq "basic.json" "dan"
=> [
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    8
]

> jq "basic.json" "dan[1]"
=> 2

Using jq with a URL

> jq "https://official-joke-api.appspot.com/jokes/ten" [].join('.....',[setup,punchline])
=> [
    "Lady: How do I spread love in this cruel world?.....Random Dude: [...\ud83d\udc98]",
    "Why are skeletons so calm?.....Because nothing gets under their skin.",
    "How come a man driving a train got struck by lightning?.....He was a good conductor.",
    "What do you call a pig with three eyes?.....Piiig",
    "How do you steal a coat?.....You jacket.",
    "Did you hear about the submarine industry?.....It really took a dive...",
    "What does a pirate pay for his corn?.....A buccaneer!",
    "A programmer puts two glasses on his bedside table before going to sleep......A full one, in case he gets thirsty, and an empty one, in case he doesn’t.",
    "How did the hipster burn the roof of his mouth?.....He ate the pizza before it was cool.",
    "Did you hear the news?.....FedEx and UPS are merging. They’re going to go by the name Fed-Up from now on."
]

Using jq with inline json

> jq '{"a": {"b": {"c": {"d": "value"}}}}' a.b.c.d
=> value

Special Keys / Expressions

@ - Current Node (eg. current number/string/array/object) used to evaluate or check value

& - Expression (Function or Keyname) (eg. &to_number() or &keyname)

! - NOT Expression

&& - AND expression

|| - OR expression

{'ab':true} - Literal Expressions (this will be converted to json)

'foo' - Raw String Literals not evaluated (Single Quotes)

Available Functions

Generic Functions

length, reverse, type, not_null

CommandBox> jq [1,2,3,4,5,6,7,8,9] length(@)
=> 9

Conversion Functions

to_list, to_array, to_string, to_number

CommandBox> jq [1,2,-3,4,-5,6,-7,-8,9] [].to_string(@)
> [
    "1",
    "2",
    "-3",
    "4",
    "-5",
    "6",
    "-7",
    "-8",
    "9"
]

String / Number Functions

abs, ceil, floor

CommandBox> jq [1,2,-3,4,-5,6,-7,-8,9] [].abs(@)
=> [
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    8,
    9
]

Boolean Checks

ends_with, starts_with, contains

CommandBox> jq [1,2,-3,4,-5,6,-7,-8,9] [?contains('-8',@)]
=> [
    -8
]

All functions can be used in other functions with the "&" operator.

A common example would be getting a person with the highest or lowest networth max_by(people, &abs(net_worth))

Array Functions

avg, first, join, last, matches, min, max, reverse, sum, sort, split, unique/uniq

CommandBox> jq [1,2,-3,4,-5,6,-7,-8,9] avg(@)
-0.111111111111

Struct or Array of Structs functions

defaults, from_entries, group_by, key_contains, keys, map, max_by, merge, min_by, omit, pluck, sort_by, to_entries, values

# jsonfile.json
[
     {
        "logdir":"logs/aa",
        "Size":308
    },
    {
        "logdir":"logs/bb",
        "Size":303
    }
]

CommandBox> jq jsonfile.json sort_by(@,&Size)
=> [
    {
        "logdir":"logs/bb",
        "Size":303
    },
    {
        "logdir":"logs/aa",
        "Size":308
    }
]