jsonq - a concise, self-contained library to query line-delimited JSON
Suppose you have newline-separated JSON blobs in a file. Filter down this data to what you want!
$ echo '
> {
> "age": 22,
> "weightLbs": 175,
> "name": {
> "first": "John",
> "last": "Doe"
> }
> }
> ' | ./jsonq .name.first
"John"A query is a chain of operators.
For the short of patience, here is the grammar.
query = (dict_operator | list_operator | every_in_list_operator) (query | "")
dict_operator = "." /\w+/
list_operator = "[" /\d+/ "]"
every_in_list_operator = "[*]"
Given an object, .key filters to the value of the key given.
$ echo '{"key": "value"}' | ./jsonq .key
"value"Given a list, [index] filters to the single value at index.
$ echo '["first"]' | ./jsonq [0]
"first"Given a list, [*] unpacks the list.
$ echo '[1, 2, 3]' | ./jsonq [*]
1 2 3This operator has limited uses. But suppose each blob contains a list of structures that we're trying to boil down.
$ echo '[{"name": "jack"}, {"name": "jill"}]' | ./jsonq [*].name
"jack" "jill"You can choose which delimiter to use for multiple results of the same blob with -d or --delimiter:
$ echo '[1, 2, 3]' | ./jsonq [*] --delimiter="\n"
1
2
3This is currently only useful for the [*] operator.
Suppose we don't just want to see the result of the query, we also
want to see what was the path of selections that the query took. Use
-f or --filter:
$ echo '{"grr": {"hello": [5, 6]}, "snafu": [{"zzz": 6}, {"aaa": 5}]}' | ./jsonq .grr.hello --filter
{"grr": {"hello": [5, 6]}}$ echo '{"grr": {"hello": [5, 6]}, "snafu": [{"zzz": 6}, {"aaa": 5}]}' | ./jsonq .grr.hello[0] --filter
{"grr": {"hello": [5]}}$ echo '{"grr": {"hello": [5, 6]}, "snafu": [{"zzz": 6}, {"aaa": 5}]}' | ./jsonq .grr.hello[1] --filter
{"grr": {"hello": [6]}}Just an assortment of examples.
$ echo '{"grr": {"hello": [5, 6]}, "snafu": [{"zzz": 6}, {"aaa": 5}]}' | ./jsonq .snafu[0].zzz .snafu[1].aaa .snafu[1].aza
6 5$ echo '[{"derp": [1, 2, 3]}]' | ./jsonq [0].derp[1]
2$ echo '{"grr": {"hello": [5, 6]}, "snafu": [{"zzz": 6}, {"aaa": 5}]}' | ./jsonq .grr.hello
[5, 6]$ echo '[["Aaron", "Amelie"], ["Brian", "Bartholomew"]]' | ./jsonq "[*][*]"
"Aaron" "Amelie" "Brian" "Bartholomew"