How to iterate through json in bash script - json

Question

I have the json as below, i need to get only the mail from the above json in bash script
value={"count":5,"users":[{"username":"asa","name":"asa
Tran","mail":"asa#xyz.com"},{"username":"qq","name":"qq
Morris","mail":"qq#xyz.com"},{"username":"qwe","name":"qwe
Org","mail":"qwe#xyz.com"}]}
Output can be as
mail=asa#xyz.com,qq#xyz.com,qwe#xyz.com
All the above need to be done in the bash script (.sh)
I have already tried with the array iteration as but of no use
for key in "${!value[#]}"
do
#echo "key = $key"
echo "value = ${value[$key]}"
done
Even i have tried with the array conversion as
alias json-decode="php -r
'print_r(json_decode(file_get_contents(\"php://stdin\"),1));'"
value=$(curl --user $credentials -k $endPoint | json-decode)
Still i was not able to get the specific output.

Answer 1

jq is the tool to iterate through a json. In your case:
while read user; do
jq -r '.mail' <<< $user
done <<< $(jq -c '.users[]' users.json)
would give:
asa#xyz.com
qq#xyz.com
qwe#xyz.com
NOTE: I removed "value=" because that is not valid json. Users.json contains:
{"count":5,"users":[{"username":"asa","name":"asa Tran","mail":"asa#xyz.com"},{"username":"qq","name":"qq Morris","mail":"qq#xyz.com"},{"username":"qwe","name":"qwe Org","mail":"qwe#xyz.com"}]}

Answer 2

If this is valid json and the email field is the only one containing a # character, you can do something like this:
echo $value | tr '"' '\n' | grep #
It replaces double-quotes by new line character and only keeps lines containing #. It is really not json parsing, but it works.
You can store the result in a bash array
emails=($(echo $value | tr '"' '\n' | grep #))
and iterate on them
for email in ${emails[#]}
do
echo $email
done

Answer 3

You should use json_pp tool (in debian, it is part of the libjson-pp-perl package)
One would use it like this :
cat file.json | json_pp
And get a pretty print for your json.
So in your case, you could do :
#!/bin/bash
MAILS=""
LINES=`cat test.json | json_pp | grep '"mail"' | sed 's/.* : "\(.*\)".*/\1/'`
for LINE in $LINES ; do
MAILS="$LINE,$MAILS"
done
echo $MAILS | sed 's/.$//'
Output :
qwe#xyz.com,qq#xyz.com,asa#xyz.com

Answer 4

Using standard unix toolbox : sed command
cat so.json | sed "s/},/\n/g" | sed 's/.*"mail":"\([^"]*\)".*/\1/'

Answer 5

With R you could do this as follows:
$ value={"count":5,"users":[{"username":"asa","name":"asa Tran","mail":"asa#xyz.com"},{"username":"qq","name":"qq Morris","mail":"qq#xyz.com"},{"username":"qwe","name":"qwe Org","mail":"qwe#xyz.com"}]}
$ echo $value | R path users | R map path mail
["asa#xyz.com", "qq#xyz.com", "qwe#gyz.com"]