Parsing JSON with Bash jq Issue

Question

Using bash JQ parser, Im trying parse the fields from a cURL JSON response.

In file 'a.json' has 4 'hash' values and 'b.json' has 5 'hash' values. Based on the assumption that my results will be similar to "a.json" I wrote a parser for it.

#jq -r '.info[].hashes[0].value','.info[].hashes[1].value','.info[].hashes[2].value','.info[].hashes[3].value' a.json

Sample JSON files

#a.json

{
"info": {
                "file": {
                    "Score": 4.01207390507143,
                    "file_subtype": "None",
                    "file_type": "EXE",
                    "hashes": [
                        {
                            "name": "A",
                            "value": "7e5dcd8ffdfa8d726ecbdd3c69e18230"
                        },
                        {
                            "name": "B",
                            "value": "3c6781d16dc26baf6422bb24d1cd0f650e451b99"
                        },
                        {
                            "name": "C",
                            "value": "3c6781d16dc26baf6422bb24d1cd0f650e451b99"
                        },
                        {
                            "name": "D",
                            "value": "c25561f3246ef188467a47971821bab93934842a1e2a48910db9768a2f66e828"
                        }
                    ],
                    "size": 1912
          }
}
}



 #b.json
{
"info": {
                "file": {
                    "Score": 4,
                    "file_subtype": "None",
                    "file_type": "Image",
                    "hashes": [
                      {
                            "name": "A",
                            "value": "f34d5f2d4577ed6d9ceec516c1f5a744"
                        },
                        {
                            "name": "B",
                            "value": "66031dad95dfe6ad10b35f06c4342faa"
                        },
                        {
                            "name": "C",
                            "value": "9df25fa4e379837e42aaf6d05d92012018d4b659"
                        },
                        {
                            "name": "D",
                            "value": "4a51cc531082d216a3cf292f4c39869b462bf6aa"
                        },
                        {
                            "name": "E",
                            "value": "e445f412f92b25f3343d5f7adc3c94bdc950601521d5b91e7ce77c21a18259c9"
                        }
                    ],
                    "size": 500
          }
}
}

But some times the results will be like "b.json" too and have 5 fields . when i'm trying to parse with the JQ command that i have written , Will give me only 4 fields and missing out the last value of "E".

#jq -r '.info[].hashes[0].value','.info[].hashes[1].value','.info[].hashes[2].value','.info[].hashes[3].value' b.json

Result : 

f34d5f2d4577ed6d9ceec516c1f5a744
66031dad95dfe6ad10b35f06c4342faa
9df25fa4e379837e42aaf6d05d92012018d4b659
4a51cc531082d216a3cf292f4c39869b462bf6aa

Now , How can we select only the hash values from desired 'name'.

Example : If we want to select only hash values of string 'names' B,C,E in any JSON files using JQ ?

Any suggestions please ?

glenn jackman · Accepted Answer · 2016-10-06 18:21:53Z

1

You can get all the values with this:

jq -r '.info.file.hashes[] | .value' *.json

Suppose you need only the values where name == "B"

jq -r '.info.file.hashes[] | select(.name == "B") | .value'

Suppose you need only the values where name == "B" or "C"

jq -r '.info.file.hashes[] | select(.name | in({"B":1,"C":1})) | .value'

The "in" function checks if the passed-in string is a key in the given object. The values of {"B":1,"C":1} are arbitrary. Ref: https://stedolan.github.io/jq/manual/#in

edited Oct 6, 2016 at 18:21

answered Oct 6, 2016 at 18:03

glenn jackman

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2 Comments

Arun Over a year ago

Glen : Thanks , This will give me all values exactly. If i need get the "values" from particular "name" in all the JSON files , How can i do that ?

Arun Over a year ago

Glen : Thanks Glean. Select is the option i was looking. Now got it

jq170727 · Accepted Answer · 2017-08-31 01:51:02Z

How can we select only the hash values from desired 'name'. Example : If we want to select only hash values of string 'names' B,C,E in any JSON files using JQ ?

Here is a solution which uses indices

  .info.file.hashes
| (map(.name) | [ indices($names[]) | .[] ]) as $found
| .[ $found[] ]
| .value

If this filter is in filter.jq and the sample data in a.json and b.json then

jq -M -r --argjson names '["B","C","E"]' -f filter.jq a.json b.json

produces

3c6781d16dc26baf6422bb24d1cd0f650e451b99
3c6781d16dc26baf6422bb24d1cd0f650e451b99
66031dad95dfe6ad10b35f06c4342faa
9df25fa4e379837e42aaf6d05d92012018d4b659
e445f412f92b25f3343d5f7adc3c94bdc950601521d5b91e7ce77c21a18259c9

note the first hash is duplicated in the sample data. If that is a problem it can easily be handled with unique or other post-processing.

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