json string in bash variable

Question

I am trying to use a bash variable to store json.

  testConfig=",{
    \"Classification\": \"mapred-site\",
    \"Properties\": {
        \"mapreduce.map.java.opts\": \"-Xmx2270m\",
        \"mapreduce.map.memory.mb\": \"9712\"
      }
    }"

echo $testConfig Output: ,{

If I give it in a single line it works. But i would like to store values in my variable in a clean format.

I tried using cat >>ECHO That didn't work either

Any help is appreciated as to how I can store this in order to get the output in an expected format. Thanks.

I think you can find the answer here : https://stackoverflow.com/questions/43373176/store-json-directly-in-bash-script-with-variables — Shuyuntake, Apr 24 '18 at 14:35
[Security implications of forgetting to quote a variable in bash/POSIX shells](https://unix.stackexchange.com/questions/171346/security-implications-of-forgetting-to-quote-a-variable-in-bash-posix-shells) — glenn jackman, Apr 24 '18 at 14:41
Cannot reproduce; the assignment is fine, and although you should quote the parameter expansion, that just preserves the newlines instead of replacing them with spaces. — chepner, Apr 24 '18 at 14:42
In general, you should avoid trying to produce JSON by hand; let `jq` generate it for you. `testConfig=$(jq -n '{Classification: "mapred-site", Properties: { "mapreduce.map.java.opts": "-Xmx2270m", "mapreduce.map.memory.mb": "9712"}}')`. For hard-coded snippets like this, it doesn't matter, but it's very important if you start trying to generate dynamic JSON using parameters with unknown values (e.g., `{foo: "$bar"}`). — chepner, Apr 24 '18 at 14:45
The fact that `testConfig` begins with a comma tells me you are building a larger JSON value using `testCongfig`, which makes the use of `jq` more important. — chepner, Apr 24 '18 at 14:48

hek2mgl · Answer 1 · 2018-04-24T14:42:05.277

2

You may use a here doc as described here:

read -r -d '' testConfig <<'EOF'
{
    "Classification": "mapred-site",
    "Properties": {
        "mapreduce.map.java.opts": "-Xmx2270m",
        "mapreduce.map.memory.mb": "9712"
      }
}
EOF

# Just to demonstrate that it works ...
echo "$testConfig" | jq .

Doing so you can avoid quoting.

edited Apr 24 '18 at 14:42

answered Apr 24 '18 at 14:36

hek2mgl

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Chopi · Answer 2 · 2018-04-24T14:41:16.677

0

You can use read -d

read -d '' testConfig <<EOF
,{ /
        "Classification": "mapred-site", 
        "Properties": {/
            "mapreduce.map.java.opts": "-Xmx2270m", 
            "mapreduce.map.memory.mb": "9712"
          }
        }
EOF

echo $testConfig;

edited Apr 24 '18 at 14:41

answered Apr 24 '18 at 14:36

Chopi

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json string in bash variable

2 Answers2