我如何使用jq库将字符替换为bash中的空白

Question

I am using jq command to replace "value" for corresponding "key" in a JSON file. Here in the following code snippet I have to replace v 's value corresponding to key k in the JSON object node .

  jq --arg flag "$node" \
                   --arg temp  $v \
             '(.[$flag]|.['$k'])|=$temp' properties.json > tempprop.json

The problem is if there is already a value is present then I need to pass an empty string as value. But jq parser is throwing exception saying

jq: error: properties/0 is not defined at <top-level>, line 1:
properties.json

So I don't know any other way to deal with this, appreciate any kind of help.

Thanks.

Answer 1

If v is an empty string, you need to quote its expansion. You should pass the value of $k via a variable as well, rather than attempting to interpolate it.

jq --arg flag "$node" \
   --arg temp  "$v" \
   --arg k1 "$k" \
   '(.[$flag]|.[$k1])|=$temp' properties.json > tempprop.json

As is, the unquoted expansion of empty $v "disappears", and jq sees the filter as the second argument to that --arg option, leaving properties.json to be interpreted as the filter.