json_demo.sh

gistfile1.txt

#!/usr/bin/env bash

requireProgram() {

  local functionName debugOutput
  unset ${functionName} ${debugOutput}
  functionName="${FUNCNAME[0]}"
  debugOutput=1

  command -v ${1} >/dev/null 2>&1 &&
    {
      echo >&2 "${functionName} requires ${1} and it is installed."
      return 0
    } ||
    {
      echo >&2 "${functionName} requires ${1} but it's not installed.  Aborting."
      return 1
    }
}


replaceJson() {
  local key Vallue
  local DebugOutput=0

  while [[ ${1} ]]; do
    case "${1}" in
    --json)
      json=${2}
      shift
      ;;
    --key)
      key=${2}
      shift
      ;;
    --value)
      value=${2}
      shift
      ;;
    --debug)
      DebugOutput=1
      ;;
    *)
      echo "Unknown parameter: ${1}" >&2
      return 1
      ;;
    esac

    if ! shift; then
      echo 'Missing parameter argument.' >&2
      return 1
    fi
  done

  if [[ -z ${key} || -z ${value} || -z ${json} ]] \
    ; then
    echo "${FUNCNAME}: one or more variables are undefined"
    return 1
  fi

  datestamp="$(date +%s)"
  [[ DebugOutput -ne 0 ]] && echo -e "\nkey: ${key}"
  [[ DebugOutput -ne 0 ]] && echo -e "\nvalue: ${value}"
  [[ DebugOutput -ne 0 ]] && echo -e "\njson_input: \n${json}"


  # Validate JSON
    if ! echo "$json" | jq empty; then
        echo "Invalid JSON input"
        return 1
    fi


    # Check for nested objects or arrays
    if echo "$json" | jq 'paths | select(length > 1)' | grep -q '.'; then
        echo "JSON contains nested objects or arrays"
        return 1
    fi
    local modified_json=$(echo "$json" | jq --arg key "$key" --arg value "$value" '
           .[$key] |= $value
       ')


echo -e "\nModified JSON: \n ${modified_json}"
return 0
}


requireProgram jq

_input=$(cat <<EOT

{

    "MARC": "abc",
    "PQR": "mno",
    "XYZ": "stu"
}
EOT
)

# replaceJson --json "${_input}" --value Siva --key MARC

replaceJson --json "${_input}" --value Siva --key MARC --debug