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How to extract a string from a json file and put into a variable (Linux)

rated 0 times [ 2] [ 0] / answers: 1 / hits: 15577 / 3 Years ago, tue, november 2, 2021, 7:05:21

I have the following in one of my json file file1.json :-

{

  "$quer": {

    "args": [{

      "args": [

        "select

      db1.table1 as tab1,

      db1.table2 as tab2,

      db1.table3 as tab3

      from db1.table4 as tab4"

      ],

      "fn": "from-sql",

      "ns": "op"

    }],

    "fn": "operators",

    "ns": "op"

  }

}

I want to extract the string db1.table4 from this json file and store into a variable.

I don't know much about sed and awk. Can someone help here?

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answered 3 Years ago diket · Accepted Answer

Assume that the string you want to extract stands in the same position in every file you can use head, tail and cut commands using pipes.

For example:

$ head -6 file.json | tail -1 | cut -b 121-129

db1.table

And here is an example of a script setting the output into a variable:

#!/bin/bash

v1=$(head -6 file.json | tail -1 | cut -b 121-130)

echo "$v1"

The output of the script will be db1.table4 which is the value of V1 varaible.

You can read more about those commands here:

head command

tail command

cut command

Of course you can use those commands to extract any other string from a file.