jq: Query a JSON Inventory

EasyCommand Line Essentials10-20 min

The brief

Query a JSON inventory with jq. The data is /root/case/inventory.json, an array of host objects like {"host":"node00","role":"web","cpus":4,"active":true}. Produce three answers:

/root/case/total.txt — total number of hosts
/root/case/active.txt — number of hosts with active == true
/root/case/roles.txt — the distinct roles, sorted, one per line

The data varies per session. See /root/case/brief.txt.

What you'll do

Count records with jq 'length'
Filter with select() and count the subset
Extract a field across an array and dedupe with unique
Print raw string output with -r

Hands-on lab: you work on a real Linux box in your browser, graded on the machine's actual state.