Fourteen pages,
printable.
The references engineers reach for weekly. HTTP status codes, regex, git, kubectl, cron, SQL, shell, curl, plus Docker, redis-cli, psql, jq, tmux, and the DNS toolbox. Each fits on one A4 page, so you can print it and keep it by the keyboard.
The fourteen sheets.
One page each, laid out for print. Open one and hit ⌘P.
HTTP status codes
1xx · 2xx · 3xx · 4xx · 5xx, with what each means.
Regex
Anchors, classes, quantifiers, lookarounds, flags.
Git
Move, undo, rewrite, recover. The 30 commands that matter.
kubectl
Inspect, apply, debug, port-forward.
Cron
Five fields. The non-obvious modifiers.
SQL
Joins, window functions, CTEs, set operations.
Shell
Parameter expansion, redirection, signals, glob patterns.
curl
The flags that matter for debugging.
Docker
Images, containers, volumes, compose, cleanup.
redis-cli
The core data types, TTLs, SCAN, pub/sub, memory debugging.
psql
Meta-commands, COPY, live queries, table sizes, EXPLAIN.
jq
Selectors, pipes, map/select, string interpolation, one-liners.
tmux
Sessions, windows, panes, copy mode, the config that matters.
DNS tools
dig, host, nslookup, whois: tracing a name to an address.
Pin them somewhere.
Each sheet has its own page, laid out as a single A4. Open one, then use your browser's print preview (⌘P / Ctrl+P) to save as PDF or print and pin near your terminal.