JQ_EXAMPLES.md

Examples from a real bash history. These may not necessarily reflect good queries in jq, and there might be more idiomatic ways, yet those are the solutions a non-jq expert reached for in their partial understanding of jq.

Result set of a nested document structure

$ jq -r < contracts.json '.d.results | map(.ItemSet) | map(.results) | flatten | map(.id) | .[]'
1
2
3
4

Find a value by key in a set of documents

$ cat items/* | jq -r '[.Id,.Status] | @tsv' | grep 1 | cut -f2
up

Find document by a given key/value match

$ find items -type f | xargs -n1 -I% sh -c '(jq -r .Status < % | grep up > /dev/null) && echo %'
items/item1.json

Selecting a subset of keys

$ cat file.json | jq '[.Category,.Location,.Status]'
[
  "something",
  "here",
  "up"
]

Tabular data

$ cat items/* | jq -r '[.Id,.Status] | join(",")'  | column -ts,
1  up
2  down

Tabular data is easy if the structure is flat

$ aws ec2 describe-instances --query 'Reservations[*].Instances[*].[InstanceId,Placement.AvailabilityZone,PrivateIpAddress]' > ec2_table.json
$ cat ec2_table.json  | jq -c '.[][]'
["i-0719122123fe1","eu-central-1a","188.31.1.52"]
["i-071612ac611aa","eu-central-1c","188.40.2.7"]

Fail on missing entry

curl 'http://localhost:8080/auth/admin/realms/master/users?username=admin | jq -e 'map(select(.username == "admin")) | first'

Did not work as intended

Trying to extract two values, one of them nested ([0] and [1].Arn) from the document ec2.json. For multiple entries will batch values 0 and 1 instead of grouping by entry

$ aws ec2 describe-instances --query 'Reservations[*].Instances[*].[InstanceId,IamInstanceProfile]' > ec2_nested.json'
$ cat ec2_nested.json | jq -r '.[][][0,1]'
i-312ab1273123e
i-81a90136fbd71
{
  "Arn": "arn:aws:iam::71291811:instance-profile/my-instance",
  "Id": "AIDAJAKADD"
}
{
  "Arn": "arn:aws:iam::71291811:instance-profile/another-instance",
  "Id": "AIFALSDSAB"
}