Parse through JSON using only Bash

Question

I have a JSON file :

{
    "request_id": "9a081c0c-9401-7eca-f55d-50e3b7c0301c",
    "lease_id": "",
    "renewable": false,
    "lease_duration": 2764800,
    "data": {
        "password": "test123",
        "username": "testuser1"
    },
    "wrap_info": null,
    "warnings": null,
    "auth": null
}

I am trying to read the values of username and password. Now I was able to integrate bash and python to get what I wanted.

# curl --silent -k https://1.2.3.4:8200/v1/secret/service/clustered -H "X-Vault-Token: c2e3b6ec17df" | python3 -c "import sys, json; print(json.load(sys.stdin)['data']['password'])"
test123

# curl --silent -k https://1.2.3.4:8200/v1/secret/service/clustered -H "X-Vault-Token: c2e3b6ec17df" | python3 -c "import sys, json; print(json.load(sys.stdin)['data']['username'])"
testuser1

But since I only want to use bash, I have done the following too:

# curl --silent -k https://1.2.3.4:8200/v1/secret/service/clustered -H "X-Vault-Token: c2e3b6ec17df" | sed -n -e 's/^.*password":"//p' | cut -d'"' -f1
test123

# curl --silent -k https://1.2.3.4:8200/v1/secret/service/clustered -H "X-Vault-Token: c2e3b6ec17df" | sed -n -e 's/^.*username":"//p' | cut -d'"' -f1
testuser

I am just concerned whether I have made use of sed and cut commands correctly in this case. Or is there a better way to extract the required fields?

Why would you want to use `sed`, use `jq` a son syntax aware parser. — Inian, May 17 '17 at 18:36
Sed and `cut` are not "only Bash", they're external dependencies. If you really want a parser that's written in shell, you can have a look at [JSON.sh](https://github.com/dominictarr/JSON.sh). — Benjamin W., May 17 '17 at 20:40

score 17 · Accepted Answer · edited May 17 '17 at 18:45

17

I would recommend using jq:

$ jq '.data.password' data.json
"test123"

Or both fields:

$ jq '.data.password, .data.username' data.json
"test123"
"testuser1"

edited May 17 '17 at 18:45

chepner

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answered May 17 '17 at 18:39

grundic

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score 6 · Answer 2 · edited May 17 '17 at 18:46

6

I would recommend jq a lightweight JSON aware parser for manipulating JSON content. Pipe your curl command input to a filter in jq as

curl-command | jq --raw-output '.data.password, .data.username'

Instructions to download-and-install jq available.

edited May 17 '17 at 18:46

chepner

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answered May 17 '17 at 18:44

Inian

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1

Why is this downvoted? I'd be happy to correct if some information were incorrect – Inian Aug 10 '18 at 11:43

score 0 · Answer 3 · answered Aug 13 '18 at 12:02

0

You can use bashJson

Its a wrapper for the Python's JSON module and can handle complex JSON data.

See my answer here for example usage : https://stackoverflow.com/a/51821898/2734348

answered Aug 13 '18 at 12:02

Anand Singh

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Parse through JSON using only Bash

3 Answers3

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