Bash script print output in json format - linux

Question

I'm trying to curl a webpage and does some processing to it and in final i am trying to print in json format.(which actually needs to be in mongodb input)
so the input (which is read though curl) is
Input:
brendan google engineer
stones microsoft chief_engineer
david facebook tester
for the kind of processing, i'm assigning values to the variables ($name, $emloyer, $designation)
my final command which converts to json is,
echo [{\"Name\":\"$name\"},{\"Employer\":\"$employer\"},{\"dDesignation\":\"$designation\"}]
The current output is,
[{"Name":"brendan","Employer":"google","Designation":"engineer"}]
[{"Name":"stones","Employer":"microsoft","Designation":"chief_engineer"}]
[{"Name":"david","Employer":"facebook","Designation":"tester"}]
but, i want the output in the same line separated by comma and square brackets in the start and end (not on every lines)
Expected output:
[{"Name":"brendan","Employer":"google","Designation":"engineer"},{"Name":"stones","Employer":"microsoft","Designation":"chief_engineer"},
{"Name":"david","Employer":"facebook","Designation":"tester"}]
any suggestions.

Answer 1

Conventional text-processing tools can't do this right for the general case. There are a bunch of corner cases to JSON -- nonprintable and high-Unicode characters (and quotes) need to be escaped, for instance. Use a tool that's actually built for the job, such as jq:
jq -n -R '
[
inputs |
split(" ") |
{ "Name": .[0], "Employer": .[1], "Designation": .[2] }
]' <<EOF
brendan google engineer
stones microsoft chief_engineer
david facebook tester
EOF
...emits as output:
[
{
"Name": "brendan",
"Employer": "google",
"Designation": "engineer"
},
{
"Name": "stones",
"Employer": "microsoft",
"Designation": "chief_engineer"
},
{
"Name": "david",
"Employer": "facebook",
"Designation": "tester"
}
]

Answer 2

Something like this?
sep='['
curl "...whatever..." |
while read -r name employer designation; do
printf '%s{"Name": "%s", "Employer": "%s", "Designation": "%s"}' "$sep" "$name" "$employer" "$designation"
sep=', '
done
printf ']\n'
I do agree that this is brittle and error-prone; if you can use a JSON-aware tool like jq, by all means do that instead.

Answer 3

If you have access to jq 1.5 or later, then you can use inputs and may wish to consider using splits(" +") in case the tokens might be separated by more than one space:
jq -n -R '
[inputs
| [splits(" +")]
| { "Name": .[0], "Employer": .[1], "Designation": .[2] }]'
If you do not have ready access to jq 1.5 or later, then please note that the following will work with jq 1.4:
jq -R -s '
[split("\n")[]
| select(length>0)
| split(" ")
| { "Name": .[0], "Employer": .[1], "Designation": .[2] }]'