Knuth tablet

His writing on a tablet.

https://www.youtube.com/watch?v=vG0D-kKTF1g

https://www.quantamagazine.org/computer-scientist-donald-knuth-cant-stop-telling-stories-20200416/

Jq cheat sheet

jq .
jq type
jq keys

Samples:

cat adb_shared.json | jq keys
cat adb_shared.json | jq .ADB_Instance
cat adb_shared.json | jq .ADB_Instance | head

linux: length (count)
cat adb_shared.json | jq ".ADB_Instance | length"

jq length:
(count)
jq '.data' zcluster.json | jq length

extraer key de cada elemento del array:
iterator operator .[]

jq '.data' zadb.json |  jq '.[] | .id'
jq '.data' zadb.json |  jq '.[] | ."defined-tags"'

jq '.data' zadb.json |  jq '.[] | ."db-name"'
 

jq '.data' zadb.json |  jq '.[] | ."db-name" + " " + (."is-dedicated"|tostring) + ", " + (."defined-tags"|tostring)'
 

Names with dashes:
You need to enclose in brackets and double quotes:

cat zsl-sample1.json | jq .data | jq '."ingress-security-rules"'

funcion: tostring
has to be inside of quotation mark.

terraform output -json | jq '.elastic_endpoint.value'

alias jqq='jq --color-output < swagger.json | less'

 
remove additionalProperties for a json

jq 'walk(if type == "object" and has("additionalProperties") then del(.additionalProperties) else . end)'  < sw1.json | grep -i add
 

Samples by quering json:

[
  {
    "Id": "cb94e7a42732b598ad18a8f27454a886c1aa8bbba6167646d8f064cd86191e2b",
    "Names": [
      "condescending_jones",
      "loving_hoover"
    ]
  },
  {
    "Id": "186db739b7509eb0114a09e14bcd16bf637019860d23c4fc20e98cbe068b55aa",
    "Names": [
      "foo_data"
    ]
  },
  {
    "Id": "a4b7e6f5752d8dcb906a5901f7ab82e403b9dff4eaaeebea767a04bac4aada19",
    "Names": [
      "jovial_wozniak"
    ]
  },
  {
    "Id": "76b71c496556912012c20dc3cbd37a54a1f05bffad3d5e92466900a003fbb623",
    "Names": [
      "bar_data"
    ]
  }
]

contains:

devwebcl@devwebcl-PC ~/tmp
$ cat t.json | jq -c 'map(select(.Names[] | contains ("data"))) '
[{"Id":"186db739b7509eb0114a09e14bcd16bf637019860d23c4fc20e98cbe068b55aa","Names":["foo_data"]},{"Id":"76b71c496556912012c20dc3cbd37a54a1f05bffad3d5e92466900a003fbb623","Names":["bar_data"]}]

devwebcl@devwebcl-PC ~/tmp
$ cat t.json | jq -c 'map(select(.Names[] | contains ("data"))) | .[] .Id'
"186db739b7509eb0114a09e14bcd16bf637019860d23c4fc20e98cbe068b55aa"
"76b71c496556912012c20dc3cbd37a54a1f05bffad3d5e92466900a003fbb623"

Not contains:

devwebcl@devwebcl-PC ~/tmp
$ cat t.json | jq 'map(select(any(.Names[]; contains("data"))|not)|.Id)[]'
"cb94e7a42732b598ad18a8f27454a886c1aa8bbba6167646d8f064cd86191e2b"
"a4b7e6f5752d8dcb906a5901f7ab82e403b9dff4eaaeebea767a04bac4aada19"

devwebcl@devwebcl-PC ~/tmp
$ cat t.json | jq '. - map(select(.Names[] | contains ("data"))) | .[] .Id'
"cb94e7a42732b598ad18a8f27454a886c1aa8bbba6167646d8f064cd86191e2b"
"a4b7e6f5752d8dcb906a5901f7ab82e403b9dff4eaaeebea767a04bac4aada19"

https://github.com/stedolan/jq/wiki/Cookbook#filter-objects-based-on-the-contents-of-a-key

jq -s (slurp), concatenates json

--slurp (-s) key is needed and map() to do so in one shot

$ cat f1.json
{
  "records": [
    {"a": 1},
    {"a": 3}
  ]
}

$ cat f2.json
{
  "records": [
    {"a": 2}
  ]
}

$ jq -s 'map(.records[].a)' f?.json
[
  1,
  3,
  2
]

 

# concatenamos arrays:  
jq -s '.[0] + .[1]' sample1.json sample2.json