JSON parsing with conditional filter with jq + shell

JSON parsing with conditional filter

For e.g. We have a json as below. We want to get the "format" field value when name is "Test".

{
  "name": "maven-snapshots",
  "format": "maven2",
  "type": "proxy",
  "url": "http://<host>:<port>/repository/maven-snapshots"
}
{
  "name": "Test",
  "format": "yum",
  "type": "hosted",
  "url": "http://<host>:<port>/repository/Test"
}
{
  "name": "Test_Group",
  "format": "maven2",
  "type": "group",
  "url": "http://<host>:<port>/repository/Test_Group"
}


We can get  it by:      jq -r '.[] | select(.name=="Test") | .format' 
 This will filter the "name" field and if it matches then return the "format" field value for that array element.

We can parse this from URL by below command.

curl -s -u admin:admin123 -X GET 'http://<host>:<port>/service/rest/v1/repositories' | jq -r '.[] | select(.name=="Test")|.format'

To get the number of elements in JSON array

 jq length 

To get the type of object 

jq type 

To get values with comma separated in same line 

jq  -r '.[] | [.date, .count, .word] | @csv'

"2011-01-12 13:14",17,"This"
"2011-01-13 21:30",4711,"That"