TIL 2
jq command
A command to manipulate json files. At work we usually have a bunch json serialized ouputs in S3 or some other datastore, which are absurdly many lines long and deeply nested. Often, if I need to grep something out of it, I’ll just copy and paste it to a company internal json prettifier to make it human readable and get what I need. There must be some out on the web too. Something like this.
It’s a hassle when you need to switch multiple windows, download files, copy paste content, etc. Now come ‘jq’, a command line utility to, hopefully, end all that.
Download(on mac): brew install jq
Print full json:
>> jq '.' your_file.json
Print a level-1 keys value:
>> jq '.your_key' your_file.json
Print a level-2 keys value:
>> jq '.your_key.your_sub_key' your_file.json # and so on
Print an array element (0 indexed):
>> jq '.[4]' your_file.json # index 4 is the 5th element in a 0 indexed array
Print a range of array elements:
>> jq '.[2:6]' your_file.json # prints index 2 up until 5
Print range without bound:
>> jq '.[2:'] your_file.json # prints index 2 till the last
Print range from the right end:
>> jq '.[-3:]' your_file.json # prints the last 3 elements
Print key of an array element:
>> jq '.[4].key' your_file.json # prints the index 4's key
Print for all array elements key:
>> jq '.[].key' your_file.json # for all elements in array having 'key', all its values will get printed
There so much more power in jq, feel free to explore.