Jq

Утилита для работы с json

Установка

apt install jq

Примеры использования

Вывести список хостов заббикса, хостнейм которых заканчивается на com и сформировать json с ключами host и hostid

 jq .result | jq '.[] | select(.host|test(".com$"))' | jq '{host, hostid}'

{
  "host": "host1.example.com",
  "hostid": "10600"
}
{
  "host": "host2.example.com",
  "hostid": "10601"
}

Вывести список хостов заббикса, хостнейм которых НЕ заканчивается на com и сформировать json с ключами host и hostid

 jq .result | jq '.[] | select(.host|test(".com$")|not)' | jq '{host, hostid}'

{
  "host": "host1.example.ru",
  "hostid": "10602"
}
{
  "host": "host2.example.ru",
  "hostid": "10603"
}

Испльзовать несколько фильтров. Отобразить только включенные хосты из прошлого примера

 jq .result | jq '.[] | select((.host|test(".com$")|not) and (.status=="0"))' | jq '{host, hostid}'

{
  "host": "host1.example.ru",
  "hostid": "10602"
}

Получить sub-key по имени 'data'

$ jq .data file.json

Получить несколько sub-keys

$ jq ".data,.name" file.json

Получить несколько sub-keys в объекте вместе со значениями

jq '{program,message}' - обратите внимание на отсутствие точки

How to "de-array" something?

Place [] at the end of the key

jq .results[]

Get nth item of an array off a sub-key

1. 0th item off the .results key

jq '.results | .[0]'

Get deeply nested data

$ jq .data.product_id.value file.json

or with piping (i.e. piping and dots can substitute for one another)

$ jq ".data | .product_id | .value" file.json Key .name value for each item in a (top-level here) array

$ jq ".[] | .name" file.json

(outputs an array of names)

make sure you don't forget to include any intermediate object keys

e.g.

$ jq ".[] | .intermediate.name" file.json Merge entries from two keys

jq '.devDependencies + .dependencies' package.json

Merge entries from multiple files Get count of entities

1. Just pipe to length

$ jq '.dependencies, .devDependencies | length' package.json 16 15

   NB: notice how multiple top-level keys were used with the comma operator

Filter records that have null at a value

$ jq '.[] | select (.coreTransactionData.productId == null)' file.json

   notice use of select (conditional)

   (not null is just != instead)

Concat bits together to form one string

Use parenteses and the plus operator

jq '(.program + ":::" + .message)'

List the keys without values

jq '.properties | keys' file.json

Note that 'keys' has no dot in front of it (since it is a built-in command rather than a property of this particular piece of JSON) Warp the output of a jq filter in an array (i.e. to appear as an array of objects and be valid for import)

Transform a command like so:

jq '.[] | select ((.payload.coreTransactionData.productId != null))' paymentConfirmedEvents--FromDeals.json

into this: (i.e. wrap the entire command in the array notation, and the do the piping within this array.)

$ jq '[.[] | select ((.payload.coreTransactionData.productId != null))]' paymentConfirmedEvents--FromDeals.json

How to handle non standard key names that might conflict with built-ins

Imagine the data had keys "schema:name" (i.e. with colons in them)

1. This fails

json | jq '.schema:name'

However, wrapping in square brackets and strings works:

json | jq '.["schema:name"]'

How to handle when a key sometimes has an array and sometimes a single object

Use max to get last item in array. If it fails, ignore error with ?. Use the alternative operator // to fall back to . which (I THINK) is a no-op here.

cat ../transparenzportal-hamburg/freeformatter-out.json| jq '.events.Event[] | .eventDates.EventDate | (max? // .) .date'

Как удалить двойные кавычки в выводе

jq -r '.name'