Program devices in Python

import json
import subprocess

firmware_path = "firmware.hex"

# Program all connected jlink devices and collect the output
output = subprocess.run(["nrfutil", "device", "program",
                         "--json", "--traits", "jlink",
                         "--firmware", firmware_path],
                        capture_output=True)
stdout_as_lines = output.stdout.decode("utf-8").split("\n")[0:-1]

for line in stdout_as_lines:
    parsed_line = json.loads(line)

    # Find the lines indicating that a task ended
    if parsed_line["type"] == "task_end":
        # Print the results of the operation
        print("{}: {}".format(parsed_line["data"]["task"]["description"],
                              parsed_line["data"]["result"]))