jq — JSON Processing

JSON processing with jq across 9 disciplines. Each discipline is a directory — add sub-pages as it grows without restructuring. All commands copy-paste-runnable on Arch Linux.

Disciplines

Discipline	Description
Basics	Keys, dot access, nested paths, raw output (-r), compact (-c), iterators, pipes
Selection	select, test, has, type checks, regex filtering, compound conditions, contains, any/all
Construction	Build JSON from shell, --arg/--argjson, object construction, to_entries/from_entries, merge
Output	@csv, @tsv, @html, @json, @base64, @uri, string interpolation, join, split
Aggregation	Slurp (-s), group_by, sort_by, unique_by, min_by/max_by, add, length
Infrastructure	ip -j, nmcli, systemctl, ss, journalctl, pacman — system JSON queries
API	curl \| jq pipelines, pagination, authentication, error handling, multi-source joins
Transforms	map, reduce, recurse, walk, path expressions, env/$ENV, string transforms
Gotchas	Null handling, string vs number, empty vs null, try-catch, shell quoting, operator precedence

Discipline

Description

Basics

Keys, dot access, nested paths, raw output (-r), compact (-c), iterators, pipes

Selection

select, test, has, type checks, regex filtering, compound conditions, contains, any/all

Construction

Build JSON from shell, --arg/--argjson, object construction, to_entries/from_entries, merge

Output

@csv, @tsv, @html, @json, @base64, @uri, string interpolation, join, split

Aggregation

Slurp (-s), group_by, sort_by, unique_by, min_by/max_by, add, length