3

I have a json file named xyz.json as follows

[
    {
        "annotations": [ "a" , "b" , "c" ],
        "class": "image",
        "filename": "vc00_02201.png"
    },
    {
        "annotations": [],
        "class": "image",
        "filename": "vc00_02202.png"
    }
    {
        "annotations": [],
        "class": "image",
        "filename": "vc00_02203.png"
    },
    {
        "annotations": [],
        "class": "image",
        "filename": "vc00_02204.png"
    }
]

I need to copy the object "annotations" from "filename": "vc00_02201.png" to "annotations" of "filename": "vc00_02204.png" within the same xyz.json file using a shell script. Expected output:

[
    {
        "annotations": [ "a" , "b" , "c" ],
        "class": "image",
        "filename": "vc00_02201.png"
    },
    {
        "annotations": [],
        "class": "image",
        "filename": "vc00_02202.png"
    }
    {
        "annotations": [],
        "class": "image",
        "filename": "vc00_02203.png"
    },
    {
        "annotations": [ "a" , "b" , "c" ],
        "class": "image",
        "filename": "vc00_02204.png"
    }
]
  • Does it have to be shell script? This would certainly be easier in a scripting language with JSON support (all of the major ones, including at least Perl, Python, and Ruby). Also, if it has to be shell, which external utilities can you use? Can you use something like jq ? – derobert Jan 8 at 18:03
  • yes I can use jq and python script is also fine. – Praveen Kumar Jan 8 at 18:15
3
$cat xyz.json | jq '.[3].annotations=.[0].annotations'
  • 1
    +1, You can do jq ... xyz.json as well instead of using cat. – Haxiel Jan 9 at 7:06
  • it says xyz.json : command not found – Praveen Kumar Jan 9 at 12:53
  • don't copy the "$" sign before cat – Neo Mosaid Jan 9 at 16:20
  • It says the same with out copy of $ sign – Praveen Kumar Jan 9 at 18:20
0

this is also achievable via jtc in one line:

bash $ cat xyz.json | jtc -w'<vc00_02204.png>[-1][annotations]' -eu jtc -w'<vc00_02201.png>[-1][annotations]' xyz.json \; 
[
   {
      "annotations": [
         "a",
         "b",
         "c"
      ],
      "class": "image",
      "filename": "vc00_02201.png"
   },
   {
      "annotations": [],
      "class": "image",
      "filename": "vc00_02202.png"
   },
   {
      "annotations": [],
      "class": "image",
      "filename": "vc00_02203.png"
   },
   {
      "annotations": [
         "a",
         "b",
         "c"
      ],
      "class": "image",
      "filename": "vc00_02204.png"
   }
]
bash $ 

Of course, it could have been done via referencing direct members of array, like:

bash $ cat xyz.json | jtc -w'[3][annotations]' -eu jtc -w'[0][annotations]' xyz.json \;

but then whole point of cross-referencing by filename would be moot.

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