Merge two json in bash (no jq)

Question

I have two jsons :

env.json

{  
   "environment":"INT"
}

roles.json

{  
   "run_list":[  
      "recipe[splunk-dj]",
      "recipe[tideway]",
      "recipe[AlertsSearch::newrelic]",
      "recipe[AlertsSearch]"
   ]
}

expected output should be some thing like this :

{  
       "environment":"INT",
    "run_list":[  
          "recipe[splunk-dj]",
          "recipe[tideway]",
          "recipe[AlertsSearch::newrelic]",
          "recipe[AlertsSearch]"
       ]
    }

I need to merge these two json (and other like these two) into one single json using only available inbuilt bash commands.

only have sed, cat, echo, tail, wc at my disposal.

Answer 1

A little bit hacky, but hopefully will do.

env_lines=`wc -l < $1`
env_output=`head -n $(($env_lines - 1)) $1`
roles_lines=`wc -l < $2`
roles_output=`tail -n $(($roles_lines - 1)) $2`
echo "$env_output" "," "$roles_output"

Answer 2

Tell whoever put the constraint "bash only" on the project that bash is not sufficient for processing JSON, and get jq.

$ jq --slurp 'add' env.json roles.json