Section 1.1: jq - The Go-To JSON Processor

Without a doubt, jq is one of the most widely used tools for working with JSON. It excels at filtering and parsing JSON data, making it invaluable for shell scripts that interact with APIs. Additionally, jq is compact and incredibly efficient. Here's how you can use jq in conjunction with an API call:

When you inspect the raw output of this API call, you will see a complex JSON structure. For instance, the output might look something like this:

{"results":[{"gender":"female","name":{"title":"Mrs","first":"Alice","last":"Williams"},...}]}

By piping this output into jq, you can perform queries to extract the data you need. If you simply pass the output to jq, it will format it for easier reading. If your goal is to retrieve a random name from the API, you would do the following:

This command would yield a result like this:

{

"title": "Miss",

"first": "Charline",

"last": "Legrand"

}

Now, you have an efficient way to manipulate API responses without leaving the shell.

The capabilities of jq extend beyond basic filtering. For instance, if you wanted to create a new key called fullname that combines both first and last names, you could easily achieve this with jq:

This would return:

{

"fullname": "Charline Legrand"

}

In a manner similar to chaining shell commands, you can also combine jq filters to enhance your data processing.

Section 1.2: Introducing jo for JSON Creation

While jq is excellent for parsing existing JSON data, jo is the perfect tool for constructing JSON structures directly from the shell. This utility simplifies the process, allowing you to create JSON data without the hassle of manual string concatenation or escape sequences. Here's a quick example of how easy it is to use jo:

$ jo name=bob creation_date="$(date +%m-%d-%y)"

This command will produce:

{"name":"bob","creation_date":"02-23-21"}

Instead of manually formatting each element, you can declare items like regular variables. Jo also allows you to capture the output of subshells effortlessly.

Additionally, you can pretty print larger JSON objects using the -p option. For example:

$ jo -p arr=$(jo -a one two three four five six)

This results in:

{

"arr": [

"one",

"two",

"three",

"four",

"five",

"six"

]

}

For more information on jo and its capabilities, you can refer to its documentation.

Section 1.3: json_pp - Pretty Printing JSON

json_pp is a straightforward utility that formats larger JSON structures for better readability and can convert between various formats. When you run:

It will output a neatly formatted JSON structure like this:

{

"info" : {

"page" : 1,

"results" : 1,

"seed" : "83b8f82090d14bfb",

"version" : "1.3"

},

...

}

Although it doesn't have the extensive features of jq or jo, json_pp is useful for quickly making JSON more readable in urgent situations.

Section 1.4: jshon - A Lightweight JSON Parser

Another lightweight option for JSON manipulation is jshon, which offers functionalities similar to jq. It provides quick access to key names in a JSON object. For instance, if you want to retrieve all the keys from an object, you can use:

$ echo '{"key1":"value1","key2":"value2","key3":"value3"}' | jshon -k

This will give you:

key1

key2

key3

While jq returns the keys as an array, jshon simply outputs them as plain text. jshon is remarkably fast, outperforming jq significantly in benchmarks for the keys function.

Thanks for joining us! Processing JSON in shell scripts or directly in the console can be streamlined with these powerful utilities. For further skill enhancement, check out "6 Terminal Commands You Should Know."