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Glossary

239 terms
See also: /concepts →

.

.d.ts Files — Ambient Declarations, Asset Imports, Module Typing

Authoring .d.ts files — ambient declarations, declare module 'foo', asset typing (*.svg?raw), declare global, triple-slash refs, and the home-hero.svg?raw pattern used in this project.
typescript declarations modules ambient

@

@vue/cli — Vue 2/3 scaffolding CLI (deprecated path)

Reference for the legacy @vue/cli npm package — install, command surface, plugin model, and why create-vue + Vite is the recommended path for new projects.
npm package vue scaffolding

A

ai — Vercel AI SDK

Package-level reference for the Vercel AI SDK — streamText, generateObject, tool calling, structured output, and the multi-provider model interface.
npm package ai llm

Approvals & Sandboxing

Control what Codex CLI can do — approval policies (untrusted, on-request, never), sandbox modes (read-only, workspace-write, danger-full-access), OS-native sandbox mechanics, and --full-auto.
codex openai sandbox approvals

argparse — Stdlib CLI Argument Parser

Parse command-line arguments with Python's stdlib argparse module. Covers positional/optional args, subparsers, nargs, validation, mutually exclusive groups, FileType, env-var fallbacks, and argcomplete.
python stdlib cli scripting

arp — ARP Cache Viewer and Editor

Display, add, and delete entries in the Windows ARP (Address Resolution Protocol) cache — map IP addresses to MAC addresses, detect IP conflicts, and diagnose Layer 2 connectivity issues.
arp windows cli scripting

astro — Content-First Web Framework

Package-level reference for the Astro framework on npm — install, integration ecosystem, runtime support, and SSR/SSG adapter gotchas.
npm package astro framework

Astro — Content-First Web Framework

Astro is a multi-page, content-first web framework with an islands architecture — server-render Markdown, MDX, and component pages to static HTML, then hydrate interactive widgets selectively with React, Vue, Svelte, or Solid.
javascript framework astro ssg

attrib — File Attribute Manager

View and modify Windows file attributes (hidden, read-only, system, archive) from the command line. Covers all attribute flags, recursive operations, and practical recipes for unhiding malware-hidden files and managing backups.
attrib windows cli filesystem

axios — Promise-Based HTTP Client for Node and the Browser

Package-level reference for axios — interceptors, request configuration, error handling, and the migration story from 0.x to 1.x.
npm package http client

az — Azure CLI

Cross-platform command-line interface for managing Azure resources, running ARM-based and data-plane operations from a terminal or pipeline.
azure cloud cli devops

B

Bash — Shell Scripting Reference

Comprehensive Bash scripting reference covering variables, parameter expansion, control flow, functions, arrays, string manipulation, arithmetic, traps, process substitution, and the Bash 5.3 in-shell command substitution forms.
bash shell scripting cli

bcdedit — Boot Configuration Data Editor

View and modify the Windows Boot Configuration Data store — manage boot entries, set default OS, change timeouts, enable debugging, and configure boot options from an elevated command prompt.
bcdedit windows cli scripting

BeautifulSoup — HTML Parsing & Scraping

Parse, search, and mutate HTML/XML with BeautifulSoup 4. Covers parser choice (html.parser/lxml/html5lib), find/find_all/select, tree navigation, attribute access, and pairing with requests/httpx/playwright for end-to-end scraping.
python beautifulsoup scraping html

Big-O — Complexity Cheat Sheet for Data Structures and Algorithms

A practical Big-O reference — common data structures, algorithms, amortized analysis, space vs time, and language-specific gotchas for Python, JavaScript, and TypeScript.
big-o complexity algorithms data-structures

Biome — One toolchain for lint, format, and import sorting

Rust-based all-in-one linter and formatter for JS/TS/JSON/CSS/GraphQL. Single binary, single config, 10-100x faster than ESLint+Prettier.
javascript biome linting formatting

body-parser — HTTP Request Body Parsing for Node

Package-level reference for body-parser on npm — JSON, urlencoded, raw and text middleware, webhook signatures, and Express 4.16+ bundling.
npm package body-parser express

Branded Types — Nominal Typing in a Structural System

Branded (a.k.a. nominal, opaque, tagged) types add a phantom marker to a primitive so the compiler refuses to mix two strings — useful for IDs, units, validated input, and money. Covers hand-rolled brands, type-fest's Opaque/Tagged, Zod's .brand(), class-based brands, and runtime validation pairings.
typescript types patterns language

Bun — All-in-One JavaScript Runtime & Toolkit

Bun is a fast all-in-one JavaScript runtime, package manager, bundler, and test runner written in Zig — a drop-in replacement for Node.js and npm with built-in TypeScript and JSX support.
javascript runtime bun cli

C

caffeinate — Keep macOS Awake on Demand

Prevent display, idle, system, or user-active sleep for the duration of a command, a fixed time, or a process — without permanently changing pmset.
macos caffeinate cli power

ccusage — Claude Code & Coding-Agent Token Usage Analyzer

Local-first CLI and TypeScript library that reads JSONL session logs from Claude Code, Codex, and 13 other coding agents to produce daily/weekly/monthly/session/billing-block reports of token spend.
ccusage npm package cli

cd — Change Directory

Navigate the Windows command prompt's current working directory. Covers drive switching, absolute and relative paths, UNC paths, and path-with-spaces quoting.
cd windows cli filesystem

certutil — Certificates, Hashing and Encoding

The dual-purpose Windows CLI for certificate-store management and as the most reliable built-in tool for file hashing, base64 encoding, and CRL/CTL handling — no install required.
certutil certificates security hashing

Chain-of-Thought Prompting

CoT prompting techniques — zero-shot CoT, few-shot CoT, self-consistency, tree of thoughts, and how reasoning models compare with prompted reasoning.
chain-of-thought cot reasoning llm

chalk — Terminal String Styling for Node

Package-level reference for the chalk ANSI-styling library on npm — install, ESM-only policy, peer-deps, and alternatives.
npm package cli terminal

Chalk — Terminal string styling for Node

Apply ANSI colours, backgrounds, and text styles to terminal output in Node.js using Chalk's chainable API, plus comparisons with picocolors and patterns for building polished CLI UX.
javascript node cli terminal

chkdsk — Check Disk

Scan a FAT or NTFS volume for file system errors and bad sectors, optionally repairing them — the built-in Windows disk health and integrity tool for drives and volumes.
chkdsk windows cli scripting

Chocolatey — Windows Package Manager

Install, upgrade, pin, and script software installs on Windows with the choco CLI, packages.config files, and custom sources.
chocolatey choco package-manager install

CICS CEMT — Master Terminal Operator Reference

Drive the CICS Master Terminal transaction — INQUIRE, SET, and PERFORM verbs for programs, tasks, files, connections, and region-level operations like NEWCOPY refresh and SNAP dumps.
zos mainframe cics cemt

Claude API — Files

The Anthropic Files API — upload PDFs, images, and text once and reference them by `file_id` across multiple messages, with citations, lifecycle management, and Workbench integration.
claude api anthropic files

Claude API — Message Batches

The Anthropic Message Batches API — create, poll, retrieve, and stream results at 50% off list price for asynchronous bulk processing of thousands of Claude requests.
claude api anthropic batch

Claude API — Prompt Caching

Anthropic prompt caching — `cache_control`, 5-minute TTL, 1-hour beta, cache breakpoints, cost math, multi-turn caching patterns, and recipes for system prompts, tools, and documents.
claude api anthropic caching

Claude API — Python

Complete Python SDK reference for the Anthropic Claude API — messages, streaming, vision, extended thinking, prompt caching, batch processing, and token counting.
claude api anthropic python

Claude API — Streaming

Streaming responses from the Anthropic API — server-sent events, event types, async iteration in Python and TypeScript, partial tool input, error handling, and retry strategies.
claude api anthropic streaming

Claude API — TypeScript SDK

Complete TypeScript SDK reference for the Anthropic Claude API — install, messages.create, streaming, tool use, vision, types, and Node/Deno/Bun integration.
claude api anthropic typescript

Claude Code CLI — Complete Command-Line Reference

All claude CLI flags, startup modes, non-interactive usage, environment variables, keyboard shortcuts, subcommands, exit codes, and configuration file locations in one place.
claude-code cli reference commands

Claude Code Hooks

Automate Claude Code lifecycle events with shell hooks — PreToolUse, PostToolUse, UserPromptSubmit, Notification, Stop, SubagentStop, and PreCompact. Covers configuration, environment variables, JSON I/O, exit codes, and blocking examples.
claude-code hooks automation lifecycle

Claude Code MCP Servers

Add, configure, and build Model Context Protocol (MCP) servers for Claude Code — HTTP, SSE, and stdio transports, management commands, permission rules, and a curated list of useful servers.
claude-code mcp model-context-protocol tools

Claude Code Overview

Install, configure, and use Claude Code — Anthropic's agentic CLI. Covers interactive mode, headless scripting, CLAUDE.md memory files, the project/user settings hierarchy, IDE integration, and authentication.
claude-code cli agentic anthropic

Claude Code Power-User Tips

Advanced Claude Code workflows — effective CLAUDE.md authoring, custom skills, multi-agent patterns, headless scripting, cost control, keyboard shortcuts, prompt caching, and daily workflow techniques.
claude-code tips workflow productivity

Claude Code Settings and Permissions

Complete settings.json schema for Claude Code — permission rules, tool allowlists/denylists, environment variables, hooks, MCP, statusline, model selection, and file precedence.
claude-code settings permissions configuration

Claude Code Skills

Author and load custom Claude Code skills — how skills are discovered, the SKILL.md schema, available-skills list, packaging, project-vs-user scope, plugin namespacing, and the difference from slash commands.
claude-code skills plugins extensions

Claude Code Slash Commands

Complete reference for every built-in Claude Code slash command — session control, context management, configuration, tools, MCP, and authoring custom commands with arguments.
claude-code slash-commands cli reference

Claude Code Statusline

Customise the Claude Code statusline — settings.json keys, the JSON context passed to scripts, available variables (model, session id, cwd, branch, cost), and example scripts in bash, python, and Node.
claude-code statusline customisation prompt

Claude Code Subagents

Spawn isolated subagents with the Task tool — Plan, Explore, general-purpose, project-defined agents, isolation modes including worktrees, background runs, and orchestration patterns.
claude-code subagents task agent

Claude Tool Use (Function Calling)

Define tools, handle tool calls, run agentic loops, use parallel tools, and manage errors with the Claude API.
claude tool-use api anthropic

cls — Clear Console Screen

Clear all text from the cmd.exe or PowerShell console window and reset the cursor to the top-left — the single command for resetting a terminal session's visible output.
cls windows cli scripting

Code Review — Checklists, Heuristics, and PR Etiquette

A practical guide to reviewing and authoring pull requests — small PRs, naming, control flow, error paths, security, performance, and GitHub PR conventions.
code-review pr github pull-request

codesign — macOS Code Signing, Notarization & Stapling

End-to-end macOS distribution pipeline — sign binaries and app bundles with codesign, notarize with notarytool, staple tickets with stapler, and verify Gatekeeper acceptance with spctl.
codesign macos security signing

Codex CLI Overview

Install and use OpenAI's Codex CLI — the open-source agentic coding tool. Covers authentication, interactive mode, headless exec, ~/.codex/ layout, and AGENTS.md project memory.
codex openai cli agentic

Codex Configuration

Complete config.toml reference for Codex CLI — model selection, approval policies, sandbox modes, profiles, MCP server stubs, shell environment, notify hooks, and project trust levels.
codex openai config toml

codex exec — Non-Interactive Mode

Complete reference for codex exec — scripted invocation, stdin piping, JSON event streams, output formats, exit codes, timeouts, and automation patterns for CI, git hooks, and shell pipelines.
codex openai exec non-interactive

Codex MCP Servers

Add and configure Model Context Protocol (MCP) servers in Codex CLI — config.toml [mcp_servers.*] reference, the codex mcp subcommand, per-server tool approval modes, and the /mcp runtime command.
codex openai mcp model-context-protocol

Codex Slash Commands

Complete reference for every built-in Codex CLI slash command — session control, model switching, sandboxing, MCP management, and TUI utilities.
codex openai slash-commands cli

Codex Sub-Agents & Task Delegation

How Codex CLI supports delegating to child agents — the experimental /agent system, codex exec as a sub-agent pattern, MCP-mediated agent-to-agent calls, isolation boundaries, and orchestration patterns.
codex openai subagents agents

Codex Tips & AGENTS.md

Advanced Codex CLI workflows — AGENTS.md authoring, profiles, experimental hooks, notify callbacks, non-interactive exec scripting, session resume and fork, and codex cloud.
codex openai tips workflow

commander — Node.js Command-Line Builder

Package-level reference for the commander CLI framework on npm — install, version policy, TypeScript extras, and alternatives.
npm package cli commander

Commander.js — Node.js Command-Line Interfaces

Build full-featured Node.js CLIs with positional arguments, typed options, subcommands, auto-generated help, lifecycle hooks, and a distributable bin in package.json.
javascript node cli commander

copy — Copy Files

Copy one or more files to a new location in the Windows command prompt. Covers single-file copy, wildcard batches, file concatenation, and binary vs ASCII modes.
copy windows cli filesystem

cors — CORS Middleware for Node

Package-level reference for cors on npm — preflight handling, credentialed requests, dynamic origins, and Express integration.
npm package cors express

cron — Scheduled Jobs

Time-based job scheduler on Unix. Covers crontab syntax, user vs. system crontabs, environment quirks, logging, anacron, and the modern systemd timer alternative.
cron scheduling sysadmin cli

D

dataclasses — Boilerplate-Free Classes

Define typed data containers with @dataclass — frozen, slots, kw_only, default_factory, __post_init__, asdict, replace, and how it compares to attrs, pydantic, NamedTuple, TypedDict.
python stdlib typing

datetime — Dates, Times, Timezones

Work with dates, times, and timezones in Python using the stdlib datetime module and zoneinfo. Covers aware vs naive datetimes, ISO-8601 parsing, strftime/strptime, timedelta arithmetic, and DST handling.
python stdlib time timezones

Day.js — Tiny, immutable date library

Parse, format, manipulate, compare, and convert timezones for dates in JavaScript using Day.js — a 2 kB Moment-compatible alternative with a plugin-based architecture.
javascript dates time library

dayjs — Tiny Immutable Date Library

Package-level reference for the Day.js date library on npm — install, plugin model, version policy, and alternatives.
npm package date time

Db2 SPUFI — Interactive SQL, DSN commands, BIND, and catalog queries on z/OS

Run SQL through SPUFI, drive Db2 with DSN subsystem commands, BIND packages and plans, schedule DSNTEP2 in JCL, query the SYSIBM catalog, and generate DCLGEN.
db2 sql spufi dsn

Declaration Merging — Interfaces, Namespaces, Modules, Globals

Deep dive into TypeScript declaration merging — interface merging, namespace + class, namespace + function, module augmentation, global augmentation, and the Express Request pattern.
typescript declarations modules patterns

defaults — macOS Preferences From the Command Line

Read, write, search, and delete macOS preference plists with the `defaults` CLI: data types, domains, current-host scope, the killall dance, finding undocumented keys via plist diffing, and a curated bootstrap recipe.
macos customization prefs web-researched

defrag — Disk Defragmenter CLI

Analyze, defragment, and optimize volumes from the command line — consolidate free space on HDDs, issue TRIM on SSDs, and schedule or review optimization tasks.
defrag windows cli scripting

del — Delete Files

Delete one or more files from the Windows command prompt. Covers wildcards, quiet mode, attribute overrides, recursive deletion patterns, and the distinction from rmdir.
del windows cli filesystem

Deno — Secure JavaScript & TypeScript Runtime

Deno is a secure, modern JavaScript and TypeScript runtime built on V8 with permission-based sandboxing, built-in TypeScript, a curated standard library on JSR, and a complete toolchain (fmt, lint, test, bench, compile).
javascript runtime deno typescript

Design Patterns — Gang-of-Four Essentials and Modern Variants

A practical reference for classic OOP design patterns — Strategy, Observer, Factory, Adapter, Decorator, Repository — with examples in Python, TypeScript, and Go.
design-patterns oop architecture gof

DFSMShsm — Hierarchical Storage Manager

Migrate, recall, back up, and recover datasets across ML0/ML1/ML2 tiers with TSO H-commands and ARC operator commands; bulk-recall recipes, recall timing, and audit messages.
zos mainframe hsm dfsmshsm

DFSORT — Sort, Merge, and ICETOOL

IBM DFSORT control statements and ICETOOL operators for sorting, merging, joining, and reshaping batch datasets on z/OS.
dfsort sort icetool zos

diff2html-cli — Beautiful HTML Diffs from the Terminal

Convert unified diffs and git diff output into styled HTML side-by-side or line-by-line diff views from the command line.
diff html cli tooling

diff2html-cli — HTML Diffs from the Terminal

Package-level reference for the diff2html-cli renderer on npm — install, runtime support, peer-deps, and alternatives.
npm package diff html

dig — DNS Lookup Toolkit

Query DNS records of any type from any resolver — A, AAAA, MX, TXT, NS, SOA, SRV, CAA — with formatted output, reverse lookups, and full delegation tracing.
dig dns networking cli

dir — List Directory Contents

Display files and folders in a directory with filtering, sorting, formatting, and recursive traversal options. The Windows cmd.exe equivalent of Unix ls.
dir windows cli filesystem

Discriminated Unions — Tagged Variants & Exhaustiveness

Discriminated unions model finite states with a shared literal tag, enabling exhaustive narrowing in switch statements, Result-style error handling, reducer actions, and pattern-matched API responses.
typescript types patterns narrowing

diskpart — Disk Partition Manager

Create, delete, format, extend, shrink, and assign drive letters to disk partitions from the Windows command prompt using an interactive or scripted REPL interface.
diskpart windows cli scripting

diskutil — macOS Disk & APFS Management

Command-line front-end to Disk Utility on macOS — list, partition, format, repair, encrypt, and snapshot APFS containers, plus build and tear down software RAID volumes.
diskutil macos disk apfs

dism — Deployment Image Servicing and Management

Service Windows images and the running OS — enable/disable optional features, repair the component store, mount and edit WIM/ESD images, add drivers, and manage editions from an elevated command prompt.
dism windows cli sysadmin

dotenv — Environment Variables from .env Files

Load configuration and secrets from .env files into process.env at startup, with multi-environment files, variable expansion, schema validation, and Node 20.6+ built-in --env-file alternatives.
javascript node config env

dotenv — Load .env files into process.env

Package-level reference for the dotenv config loader on npm — install, native Node alternatives, dotenvx successor, and gotchas.
npm package config env

driverquery — List Installed Drivers

Display all installed device drivers on a local or remote Windows machine — module name, type, link date, and driver file path — for hardware audits and troubleshooting.
driverquery windows cli scripting

drizzle-orm — TypeScript SQL Toolkit

Package-level reference for Drizzle ORM — schema definitions, type-safe queries, relations, migrations with drizzle-kit, and deployment patterns.
npm package orm sql

duti — Set Default Applications on macOS

Drive macOS Launch Services from the command line — assign default apps for UTIs, file extensions, and URL schemes; understand the viewer/editor/all/shell/none roles; bulk-load file associations from a settings file; rebuild the Launch Services database when changes refuse to stick.
duti macos cli launch-services

E

echo — Output Text and Control Command Echo

Print text to stdout, expand environment variables, write blank lines, redirect output to files, and toggle command-echoing in cmd.exe batch scripts.
echo windows cli scripting

effect — TypeScript Library for Effect Systems

Package-level reference for the Effect library — Effect values, generators, fibers, error channels, dependency injection, and the 2.x → 3.x migration.
npm package effect typescript

elysia — Ergonomic Bun-Native Web Framework

Package-level reference for Elysia — end-to-end type safety, plugins, Eden RPC client, schema validation, and Bun-first deployment.
npm package web framework

Essential Python Packages

Overview of the 34 most useful Python packages — HTTP clients, data science, web frameworks, orchestration, testing, and tooling. Each has its own dedicated page with examples.
python packages pip overview

express — Minimalist Node.js Web Framework

Package-level reference for Express on npm — install, middleware model, Node support, 4-to-5 migration, and production deployment.
npm package express web

F

fastify — High-Performance Node Web Framework

Package-level reference for the Fastify framework on npm — install, plugin model, Node support, and validation/encapsulation gotchas.
npm package fastify web

Fastify — Node Web Framework

Fastify is a high-performance Node.js web framework with schema-driven validation, plugin encapsulation, hooks, decorators, and built-in Pino logging — covering routes, plugins, hooks, error handling, and production hardening.
javascript node backend framework

fc — File Compare

Compare two text or binary files line-by-line or byte-by-byte and report their differences — the built-in Windows equivalent of Unix diff for quick file audits in cmd.exe.
fc windows cli scripting

Few-Shot Prompting

In-context learning techniques — example selection, format design, count tuning, dynamic retrieval of demonstrations, and pitfalls of few-shot prompting.
few-shot in-context-learning icl prompting

Filesystems — Inodes, Links, Journaling, ext4/XFS/Btrfs/ZFS/APFS/NTFS

Core filesystem concepts every operator should know: inodes, directory structure, hard vs symbolic links, journaling, copy-on-write, and a head-to-head of ext4, XFS, Btrfs, ZFS, APFS, and NTFS with mount options and pitfalls.
filesystem inode ext4 xfs

findstr — Search Text in Files

Search for string patterns inside files or piped input on Windows — the built-in grep equivalent for cmd.exe, with support for regular expressions, case-insensitive matching, and recursive directory searches.
findstr windows cli scripting

fsutil — File System Utility

Inspect and manage NTFS file system internals — query volume info, manage hard links, sparse files, reparse points, the USN journal, and the dirty bit — from an elevated command prompt.
fsutil windows cli scripting

G

GDG — Generation data groups for rolling datasets

Define, reference, and clean up z/OS generation data groups via IDCAMS — relative generations, rollover behaviour, model DSCBs, and the modern GDGEXTENDED mode.
zos mainframe gdg datasets

getmac — MAC Address Query

Display the MAC (hardware) addresses and associated transport names for all network adapters on a local or remote Windows machine — useful for asset inventory, DHCP reservation setup, and network access control.
getmac windows cli scripting

gpg — OpenPGP Encryption & Signing

Practical GnuPG cheat sheet — generate keys, sign and verify files, encrypt for a recipient, sign git commits and tags, and manage trust without the bureaucracy.
gpg security crypto signing

gpresult & gpupdate — Group Policy Diagnostics and Refresh

Inspect the Resultant Set of Policy that applied to a user and computer with gpresult, then force a refresh with gpupdate — including HTML reports, scope filtering, and the classic 'why didn't my GPO take effect?' workflow.
gpresult gpupdate windows cli

H

Homebrew — The Missing Package Manager for macOS

Install, search, upgrade, pin, tap, bottle, and bundle packages with Homebrew on macOS: formulae vs casks, brew services, Brewfile-driven machine bootstrap, Apple-Silicon vs Intel prefixes, brew doctor, brew cleanup, and recovery recipes.
macos package-manager cli web-researched

hono — Small, Fast Web Framework for Edges

Package-level reference for Hono — minimal routing, typed handlers, middleware, RPC client, and deployment to Cloudflare Workers, Bun, Deno, Node, and Vercel Edge.
npm package web framework

hostname — Print Machine Name

Display the DNS hostname of the local Windows machine from the command prompt — useful in scripts to identify the machine without parsing systeminfo output.
hostname windows cli scripting

I

icacls — ACL Editor

Display and modify NTFS access control lists on files and directories — grant, deny, or remove permissions for users and groups, manage inheritance, and save or restore full ACL sets.
icacls windows cli scripting

IDCAMS — Access Method Services for VSAM

Define, copy, list, alter, and delete VSAM clusters and general datasets — the everyday utility for catalog and dataset lifecycle on z/OS.
zos mainframe vsam idcams

IEBCOPY — Partitioned dataset copy, compress, and unload

IBM utility for copying, merging, compressing, unloading, and reloading PDS and PDSE libraries on z/OS, including member selection, rename, and exclusion.
zos mainframe iebcopy datasets

infer Keyword — Extracting types from patterns

TypeScript's infer keyword declares a fresh type variable inside a conditional type, letting you pull a sub-type out of a matched shape. It powers ReturnType, Parameters, Awaited, and most advanced type extractors.
typescript types advanced language

ioredis — Battle-Tested Redis Client for Node

Package-level reference for ioredis on npm — cluster, sentinel, pipelining, Lua scripts via defineCommand, and stability characteristics.
npm package redis cluster

ipconfig — IP Configuration

Display and manage TCP/IP network configuration for all adapters on a Windows machine — covers full adapter details, DNS cache operations, and DHCP lease management.
ipconfig windows cli networking

ISPF Edit — Primary commands, line commands, macros, and column-mode editing

Deep dive into the ISPF editor — primary commands, line commands, BNDS/CC/MM column edits, ISREDIT macro services, profile management, and recovery.
ispf editor zos mainframe

itertools & functools — Functional Toolbelt

The two stdlib modules every Python developer pairs together — iterator algebra (chain, groupby, batched, pairwise) and function plumbing (lru_cache, partial, reduce, singledispatch, cached_property).
python stdlib functional itertools

J

JCL DD Statement — Deep Reference

Comprehensive reference for the JCL DD statement: DSN, DISP, DCB, SPACE, UNIT, VOL=SER, concatenation, DUMMY, SYSOUT, KEYLEN.
jcl dd-statements zos mainframe

JCL Quick Reference

Job Control Language syntax, common statements, EXEC, DD, and SYSOUT patterns.
jcl zos mainframe batch

JES2 — Operator commands and subsystem control

z/OS Job Entry Subsystem 2 operator slash-commands for jobs, initiators, output, classes, NJE, and spool — from the console and from SDSF.
zos mainframe jes2 operators

json — Stdlib JSON Encoder/Decoder

Encode and decode JSON in Python with the stdlib json module. Covers dumps/loads, indent/sort_keys/separators, custom default= and JSONEncoder, object_hook decoding, JSONL streaming, and orjson/ujson/msgspec comparison.
python stdlib json data

L

launchctl — Managing launchd Agents and Daemons

Bootstrap, bootout, kickstart, print, and enable/disable services with launchctl on macOS: agents vs daemons, plist anatomy, user/system domains, RunAtLoad vs KeepAlive vs StartInterval vs StartCalendarInterval, and recipes for periodic scripts and on-demand workers.
macos sysadmin services web-researched

LLM Evaluations

Build production evaluation pipelines for LLM applications — golden datasets, LLM-as-judge, rubrics, statistical significance, regression detection, and evals vs tests.
evals evaluation llm-as-judge golden-dataset

logging — Stdlib Logging

Configure Python's built-in logging module — loggers, handlers, formatters, dictConfig, rotation, structured records, and how it compares to loguru.
python stdlib logging

logman — Performance Monitor CLI

Create, start, stop, and manage Data Collector Sets for performance counters, event traces, and configuration data — the command-line interface to Windows Performance Monitor for scripted monitoring and automated log collection.
logman windows cli scripting

M

mdfind — Spotlight Search From the Terminal

Query macOS's Spotlight index from the shell — fast name, content, and metadata search across the whole filesystem, with scope, attributes, and live-update modes.
mdfind macos search cli

Memory Management — Virtual Memory, Paging, Swap, OOM, mmap

How operating systems give every process its own address space: virtual memory and paging, swap, the OOM killer, mmap, copy-on-write, the page cache, allocator choices (glibc, jemalloc, mimalloc), and how to read memory counters in top, ps, and free.
memory virtual-memory paging swap

mkdir / md — Make Directory

Create one or more directories from the Windows command prompt. Covers single and nested directory creation, batch patterns, and common scripting idioms.
mkdir windows cli filesystem

mongoose — MongoDB ODM for Node

Package-level reference for mongoose on npm — schemas, models, transactions, populate, indexes, and 7-to-8 migration.
npm package mongoose mongodb

mountvol — Volume Mount Point Manager

List, create, and remove NTFS volume mount points and display the unique volume GUID path for any drive letter or directory junction from the command prompt.
mountvol windows cli scripting

move — Move and Rename Files

Move files to a new location or rename them within the Windows command prompt. Covers single files, wildcards, directory renames, overwrite control, and cross-drive behaviour.
move windows cli filesystem

mysql2 — Fast MySQL & MariaDB Driver for Node

Package-level reference for mysql2 on npm — promise API, prepared statements, pooling, streaming, and migration from mysql.
npm package mysql mariadb

N

nano — Friendly Terminal Text Editor

GNU's small, on-screen-hinted terminal text editor — the default modal-free alternative to vi/emacs that you can drive without ever learning a command vocabulary.
nano editor cli text

ncu — npm-check-updates CLI for dependency upgrades

The ncu CLI from npm-check-updates rewrites package.json to bump dependency versions — interactive mode, filters, doctor rollback, and workspaces support.
ncu npm upgrade dependencies

net localgroup — Local Group Manager

Create, delete, and modify local security groups on a Windows machine — add or remove members, list group memberships, and manage built-in groups from the command prompt.
net-localgroup windows cli scripting

net user — Local User Account Manager

Create, modify, delete, and list local Windows user accounts from the command prompt — set passwords, manage account expiry, lock/unlock accounts, and control logon hours.
net-user windows cli scripting

netsh — Network Shell

Configure network interfaces, firewall rules, wireless profiles, port proxies, and Winsock settings from an elevated command prompt — the comprehensive Windows network configuration CLI.
netsh windows cli scripting

netstat — Network Connections and Statistics

Display active TCP/UDP connections, listening ports, routing tables, interface statistics, and per-connection process IDs from the Windows command prompt.
netstat windows cli networking

Networking Stack — OSI/TCP-IP, Sockets, TCP/UDP, MTU, NAT, DNS

How packets actually move: the OSI and TCP/IP layer models, the BSD socket API, TCP vs UDP, the three-way handshake, MTU/MSS, NAT and port translation, basic IP routing, and the full DNS resolution flow.
networking osi tcp-ip sockets

networksetup — macOS Network Configuration

Script every aspect of macOS network configuration — Wi-Fi joining, DNS servers, proxies, locations, and service order — from a single first-party command-line tool.
networksetup macos networking wifi

next — Full-Stack React Framework

Package-level reference for Next.js — App Router, server components, server actions, middleware, caching, and the 14 → 15 → 16 migration path.
npm package react framework

node:fs — File System

Node.js file system module — the three APIs (callback, sync, promises), reading and writing files, directory operations, watchers, atomic writes, and path module pairing.
javascript node filesystem fs

node:stream — Streams

Node.js streams — Readable, Writable, Duplex, and Transform, the modern pipeline() API, backpressure, async iterators, Web Streams interop, and patterns for piping files, HTTP bodies, and gzip compression.
javascript node streams pipeline

npm-check-updates — Upgrade package.json dependencies

Package-level reference for npm-check-updates on npm — install, Node support, the ncu binary, doctor mode, workspaces, and where it fits next to npm outdated, taze, and bun update.
npm package ncu upgrade

nslookup — DNS Query Tool

Query DNS servers for A, AAAA, MX, TXT, NS, PTR, and other resource records from the Windows command prompt — the built-in tool for diagnosing name resolution issues.
nslookup windows cli networking

O

osascript — Run AppleScript and JXA From the Shell

Drive macOS GUI apps, system events, dialogs, notifications, and Finder from the terminal using AppleScript or JavaScript for Automation (JXA).
osascript applescript jxa macos

P

pathping — Combined Traceroute and Ping

Trace the route to a destination and measure per-hop packet loss and latency over a sustained sampling period — more diagnostic than tracert and more thorough than ping for identifying intermittent network problems.
pathping windows cli scripting

pbcopy & pbpaste — macOS Clipboard CLI

Pipe data into and out of the macOS pasteboard from the shell — multi-pasteboard targets, newline handling, shell aliases, and real-world copy-paste recipes.
pbcopy pbpaste macos cli

PCRE — Perl Compatible Regular Expressions

PCRE2 syntax reference — character classes, quantifiers, anchors, groups, lookarounds, backreferences, flags, and advanced features used in grep, sed, nginx, PHP, and dozens of other tools.
pcre regex grep linux

pdb — Python Debugger

Pause, inspect, and step through Python programs with pdb. Covers breakpoint(), command reference, post-mortem debugging, conditional breakpoints, and enhanced alternatives like ipdb, pdbpp, and pudb.
python pdb debugging stdlib

permissions — chmod, chown, umask, ACLs

POSIX file permissions on Linux. Covers symbolic and octal chmod, ownership with chown, the meaning of r/w/x for files vs. directories, setuid/setgid/sticky bits, umask, ACLs, capabilities, and immutable attributes.
permissions chmod chown umask

pg — Native PostgreSQL Client for Node

Package-level reference for node-postgres on npm — pools, parameterized queries, transactions, LISTEN/NOTIFY, and COPY streaming.
npm package postgres database

ping — Test Network Connectivity

Send ICMP echo requests to a host to test reachability, measure round-trip latency, and detect packet loss from the Windows command prompt.
ping windows cli networking

pino — Very Low Overhead Node Logger

Package-level reference for pino on npm — child loggers, redaction, transports, serializers, and migration notes.
npm package pino logging

Playwright — End-to-end browser testing across Chromium, Firefox, WebKit

Cross-browser end-to-end test runner from Microsoft with auto-waiting, role-based selectors, trace viewer, and codegen.
javascript playwright testing browser

pmset — macOS Power Management

Inspect and configure sleep, wake, hibernate, and battery behaviour on macOS. Covers per-source profiles, scheduled wake, sleep-prevention diagnostics, battery reports, and hibernate modes.
macos pmset cli power

powercfg — Power Configuration CLI

Manage Windows power plans, enable or disable hibernation, diagnose battery health and sleep failures, and generate energy efficiency reports from the command prompt.
powercfg windows cli scripting

PowerShell Built-in Variables — Automatic & Preference Variables

Complete reference for every automatic and preference variable built into PowerShell — $_, $Error, $MyInvocation, $PSCmdlet, $Host, $PSVersionTable, $ExecutionContext, and all preference variables that tune runtime behaviour.
powershell variables reference scripting

PowerShell Error Handling — try/catch, ErrorAction, and Strict Mode

Master terminating vs non-terminating errors, $ErrorActionPreference, try/catch/finally, throw vs Write-Error, transcripts, and strict mode.
powershell scripting errors debugging

PowerShell Modules — Packages, Profiles, and the Gallery

Install, discover, update, and author PowerShell modules: PowerShellGet, PSResourceGet, the Gallery, $PSModulePath, $PROFILE customisation, PSReadLine, SecretManagement, and the must-have module shortlist.
powershell modules ecosystem web-researched

PowerShell Pipelines — Objects, Not Text

Deep dive on PowerShell's object pipeline: Where-Object, Select-Object, ForEach-Object, Sort-Object, Group-Object, Measure-Object, Compare-Object, Out-GridView, parallel execution, and the two filter forms.
powershell scripting pipelines web-researched

PowerShell Remoting — Running Commands on Other Machines

Execute PowerShell against one or many remote hosts using WinRM or SSH transport, persistent sessions, credential management, and JEA.
powershell networking remoting sysadmin

PowerShell Scripting — Functions, Parameters, and Control Flow

Author production-grade PowerShell: advanced functions with [CmdletBinding()], parameter validation, pipeline-bound parameters, splatting, switch parameters, .ps1 vs .psm1, and all the control-flow constructs.
powershell scripting web-researched

pre-commit — Git Hooks for Linters and Formatters

Run linters, formatters, and validators automatically on every git commit. Covers .pre-commit-config.yaml, essential hooks (ruff, mypy, check-yaml), autoupdate, and CI integration.
python pre-commit git-hooks workflow

Prisma — Type-Safe Node.js ORM

Schema-first ORM for Node.js with auto-generated typed client, declarative migrations, relations, transactions, and seeding — for PostgreSQL, MySQL, SQLite, MongoDB, and more.
javascript typescript orm database

Processes — Fork, Exec, Signals, Zombies, Cgroups

Process lifecycle on Unix: fork/exec/wait, PIDs, signals, zombies and orphans, parent/child trees, process groups, sessions, controlling terminals, and a tour of Linux cgroups.
process fork exec signal

Prompt Engineering Patterns

Reliable prompt structures for reasoning, extraction, classification, generation, extended thinking, and vision tasks with Claude.
prompting llm ai claude

pyproject.toml — Modern Python Project Config

The canonical config file for modern Python projects — [project] metadata, [build-system] backends (setuptools, hatchling, pdm-backend, poetry-core, flit-core), [tool.*] sections, dynamic versioning, scripts, building, and publishing.
python packaging pyproject toml

R

RACF — z/OS Security Administration

TSO commands for RACF user, group, dataset, and general-resource profile administration on z/OS.
racf zos mainframe security

re — Python Regular Expressions

Python's built-in regex module — compile vs not, match/search/findall/finditer/sub, named groups, lookarounds, verbose mode (re.X), and how it differs from PCRE.
python stdlib regex re

react — UI Library for Components and Hooks

Package-level reference for the React library on npm — install, paired react-dom, server-component model, and upgrade gotchas.
npm package react ui

React Basics — Function components, hooks, and JSX

Foundational React patterns — function components, JSX, props, hooks (useState, useEffect, useRef, useContext), list rendering, and form handling — with TypeScript throughout.
javascript react ui framework

React with TypeScript — Components, hooks, generics, and forms

Type-safe React patterns — function components, prop types, children, event handlers, refs, generic components, polymorphic `as` props, and Zod-powered forms.
typescript react ui framework

react-dom — DOM Renderer for React

Package-level reference for react-dom — client/server rendering, hydration, portals, flushSync, and the React 19 root API.
npm package react dom

redis — Official Redis Client for Node

Package-level reference for node-redis on npm — pipelining, pub/sub, TTL, the v3-to-v4 API rewrite, and rate-limit patterns.
npm package redis cache

reg — Windows Registry from the Command Line

Query, add, modify, export, and import Windows registry keys and values with the built-in reg.exe — the scriptable, no-dependency tool for everything from one-off tweaks to full backup-and-restore.
reg registry cli scripting

rmdir / rd — Remove Directory

Delete empty or entire directory trees from the Windows command prompt. Covers the /S and /Q flags, force-removing read-only trees, and safe deletion patterns.
rmdir windows cli filesystem

robocopy — Robust File Copy

Production-grade file and directory synchronisation with mirroring, multi-threading, retry logic, logging, and exclusion filters. The go-to for backup scripts and deployment pipelines on Windows.
robocopy windows cli filesystem

route — IP Routing Table Manager

Display, add, delete, and modify entries in the Windows IP routing table — control how packets are forwarded between subnets, add persistent static routes, and diagnose routing failures.
route windows cli scripting

rsync — Fast Incremental File Sync

Copy and synchronise files locally or over SSH using a delta-transfer algorithm that only sends changed parts. Covers archive mode, deletion, filtering, progress, and snapshot backups.
rsync cli networking sync

runas — Run as Different User

Launch a program in the security context of a different user account — elevate to Administrator, switch to a service account, or test application behaviour under a restricted identity.
runas windows cli scripting

S

satisfies Operator — Type-check without widening

TypeScript's satisfies operator checks a value against a type while preserving its narrow literal inferred type. The middle ground between an annotation that widens and an as cast that lies.
typescript types operators language

sc — Service Control Manager CLI

Query, create, configure, start, stop, and delete Windows services from the command line — the scripting interface to the Service Control Manager, equivalent to the Services MMC snap-in but fully automatable.
sc windows cli scripting

schtasks — Task Scheduler CLI

Create, query, run, end, and delete scheduled tasks on local or remote Windows machines from the command prompt — the scripting interface to Windows Task Scheduler.
schtasks windows cli scripting

scikit-learn — Classical Machine Learning

Build classical ML pipelines with scikit-learn. Covers the estimator API, train_test_split, Pipeline, ColumnTransformer, cross-validation, metrics, and model persistence.
python scikit-learn ml data-science

Scoop — User-Scope Package Manager

Install dev tools without admin rights using Scoop — buckets, manifests, multi-version installs, and reproducible setups.
scoop package-manager dev-tools cli

SDSF — Spool Display and Search Facility

Browse, filter, and act on JES2 spool from inside ISPF — find your job, read SYSOUT, cancel, purge, and issue operator commands.
zos mainframe sdsf jes2

Security Fundamentals — Users, Permissions, Capabilities, MAC, Sandboxing

OS-level security primitives every operator should know: users and groups, file permissions, Linux capabilities, SUID/SGID, mandatory access control (SELinux, AppArmor), sandboxing concepts, least privilege, and encryption at rest vs in transit.
security users groups permissions

set — Environment Variables

Set, display, and delete cmd.exe environment variables within the current session, perform integer arithmetic with /A, and read interactive user input with /P.
set windows cli scripting

shellcheck — Shell Script Linter

Catch quoting bugs, missing checks, and POSIX portability mistakes in shell scripts. Covers every flag, severity levels, inline directives, CI/pre-commit integration, and the most common rules.
shellcheck shell scripting linting

shutdown — Shutdown, Restart, and Logoff

Initiate, schedule, abort, or force a shutdown, restart, logoff, hibernate, or sleep on a local or remote Windows machine from the command line — essential for scripted maintenance, patch automation, and remote administration.
shutdown windows cli scripting

softwareupdate — macOS Updates From the Terminal

Deep-dive on softwareupdate(8), Apple's CLI for macOS system updates — listing pending updates, installing recommended-only or specific items, scheduling, ignoring updates, installing Rosetta and Command Line Tools, and pairing with mas and brew for full system update automation.
softwareupdate macos sysadmin updates

SOLID — Five Principles for Maintainable OO Design

A modern walk-through of the SOLID principles — single responsibility, open-closed, Liskov, interface segregation, dependency inversion — with anti-examples and refactors in TypeScript and Python.
solid oop principles srp

ssh — Secure Shell Client for Windows

Connect to remote hosts, transfer files, and forward ports over an encrypted channel using the OpenSSH client built into Windows 10 and later.
ssh windows cli networking

streamlit — Data Apps in Pure Python

Build interactive web apps for data and ML in pure Python. Covers widgets, layout, session state, caching, multipage apps, and deployment patterns.
python streamlit ui dataviz

Structural Typing — Duck Typing at the Type Level

Understand TypeScript's structural type system — assignability is based on shape, not name; excess property checks are the one exception; nominal typing requires branded types or class privates.
typescript types concepts language

Structured Output

Techniques for reliable structured generation — JSON mode, schema-constrained decoding, function/tool calls as output, and validator pairing with Pydantic or Zod.
structured-output json schema pydantic

subprocess — Spawning Processes

Run external commands from Python with subprocess. Covers run vs Popen, capture_output, streaming, pipes, timeouts, env/cwd overrides, and shlex quoting safety.
python stdlib shell

Sysinternals — PsExec, Handle, ProcMon and the Sysadmin Toolkit

Bootstrap and drive the headless Sysinternals utilities — PsExec, Handle, PsList, Autoruns, ProcMon, ListDLLs — for process spelunking, file-lock hunting, autostart auditing and scripted system tracing on Windows.
sysinternals debugging sysadmin tools

system_profiler — macOS Hardware & Software Inventory

Deep-dive on system_profiler(8) — macOS's built-in inventory tool. Covers data types, text/XML/JSON output, piping into jq and plutil, common SP* probes (hardware, displays, memory, storage, USB, network, software), detail levels, and fleet inventory recipes.
system_profiler macos sysadmin inventory

systeminfo — System Information

Display detailed OS, hardware, and network configuration for the local or a remote Windows machine. Covers output formats, remote querying, filtering, and parsing in scripts.
systeminfo windows cli sysadmin

T

takeown — Take File Ownership

Transfer ownership of files and directories to the current user or the Administrators group from an elevated command prompt — a prerequisite for modifying ACLs on system-protected paths.
takeown windows cli scripting

tar — Archive & Compress

Bundle directory trees into a single archive file with optional compression. Covers create/extract/list, gzip/bzip2/xz formats, exclusions, transforms, and incremental backups.
tar cli archives compression

taskkill — Terminate Processes

End one or more running Windows processes by PID or image name from the command prompt, with options for force termination, process tree killing, filtering, and remote targets.
taskkill windows cli scripting

tasklist — List Running Processes

Display all running processes on a local or remote Windows machine with PID, memory usage, session, and optional service or module details — the cmd.exe equivalent of Task Manager for scripts.
tasklist windows cli scripting

Template Literal Types — String Algebra at the Type Level

Template literal types let TypeScript pattern-match and synthesize string types — covering Uppercase/Lowercase intrinsics, infer-based parsers (Split, Join, CamelCase), route-param extraction, JSON path keys, and typed i18n helpers.
typescript types advanced template-literals

Testing Strategies — Pyramid, Fixtures, Mocks, Property-Based, and CI Patterns

A practical guide to test design — the pyramid (unit/integration/e2e), fixture and mock patterns, property-based testing, snapshot tests, and CI strategies that scale.
testing unit-tests integration-tests e2e

timeout — Pause Script Execution

Pause a batch script for a specified number of seconds with an optional keypress bypass — a reliable replacement for the ping-delay idiom and a safer alternative to sleep in Windows CMD scripts.
timeout windows cli scripting

tmutil — Time Machine from the Command Line

Drive Time Machine backups, destinations, exclusions, local APFS snapshots, restores, and verification entirely from the terminal — without opening System Settings.
macos tmutil cli backup

tmux — Terminal Multiplexer

Run multiple persistent terminal sessions, windows, and panes inside one shell. Covers the session/window/pane mental model, default keybindings, copy-mode, and a minimal tmux.conf.
tmux cli terminal productivity

tracert — Trace Network Route

Trace the sequence of routers between your machine and a destination by sending probes with increasing TTL values — the go-to tool for locating where a network path breaks or introduces high latency.
tracert windows cli networking

ts-node, tsx & Friends — Running TypeScript Without a Build Step

Compare ts-node, tsx, Node 22.6+ --experimental-strip-types, Bun, and Deno for running .ts files directly; pick the right tool, configure watch mode, and avoid the classic ESM / type-strip pitfalls.
typescript runtime tooling node

TSO/ISPF Navigation

Complete ISPF menu options, primary commands, line commands, edit profile, utilities, DSLIST, SDSF, TSO commands, RACF, and keyboard shortcuts.
tso ispf zos mainframe

type-fest — Community utility types for TypeScript

Package-level reference for type-fest on npm — install (dev-only, pure types), TS version requirements, recursion limits, and alternatives.
npm package types typescript

type-fest — Community utility types for TypeScript

Sindre Sorhus's collection of essential TypeScript utility types — PartialDeep, ReadonlyDeep, SetOptional, RequireAtLeastOne, Merge, Tagged, JsonValue, Opaque, and dozens more — so you don't hand-roll them.
typescript library utility-types tooling

typeof & keyof — Type-level operators

TypeScript's typeof promotes a runtime value into the type position; keyof extracts the union of property keys. Together they form the backbone of type-safe lookups, enum-from-object patterns, and inferred shapes.
typescript types operators language

TypeScript Compiler API — Codegen, codemods, and AST walks

Drive the TypeScript compiler programmatically — parse SourceFiles, query the type checker, transform ASTs with the factory, and write codemods that scale across a monorepo.
typescript tooling advanced compiler

TypeScript Modules — module, moduleResolution, .mts / .cts

Deep dive into TypeScript's module system — module/moduleResolution pairs, .mts/.cts file extensions, NodeNext vs Bundler resolution, paths, and tsconfig extends.
typescript modules esm nodenext

TypeScript Project References — Composite Builds & Monorepos

Split a TypeScript codebase into composite sub-projects, build them incrementally in dependency order with tsc --build, and integrate the result with bundlers, Turborepo, and Nx.
typescript build monorepo tooling

typing — Advanced Type Hints

Go beyond list[int] and str | None. Covers Protocol, TypeVar bounds, ParamSpec, Concatenate, Self, Annotated, TypedDict with NotRequired/Required, TypeAlias, TypeGuard, TypeIs, cast, assert_type, and reveal_type.
python typing types stdlib

tzutil & w32tm — Timezone and Windows Time

Read and set the system timezone with tzutil, then query, configure, and force-sync the Windows Time service with w32tm — including NTP peer configuration and Kerberos-clock-drift recovery.
tzutil w32tm windows cli

U

USS — z/OS UNIX System Services

The UNIX side of z/OS — OMVS, ISHELL, oedit, BPXBATCH, file tagging, zFS, and bridging shell scripts to MVS batch.
zos mainframe uss omvs

V

valibot — Modular and Tree-Shakable Schema Library

Package-level reference for valibot — schemas, transforms, pipes, branding, safeParse, and the tree-shaking advantage over zod.
npm package validation schema

vercel — Frontend cloud CLI (Next.js, Functions, Edge)

Package-level reference for the vercel CLI on npm — install, Node support, command surface, project linking model, and where it fits next to wrangler / netlify-cli.
npm package vercel deploy

vercel — Vercel frontend cloud CLI

Vercel's official CLI for deploying frontend apps, managing environments, syncing env vars, tailing logs, and rolling back via alias re-pointing.
vercel deploy edge cli

vim — Modal Text Editor

Bram Moolenaar's modal editor. Covers modes, verb-noun grammar, text objects, registers, marks, windows, search-and-replace, quickfix, macros, configuration, and a high-value baseline .vimrc.
vim editor productivity cli

vue — Progressive JavaScript Framework

Package-level reference for Vue 3 — Composition API, reactivity, single-file components, the Vue 2 → 3 migration, and the broader ecosystem (Pinia, Vue Router, Nuxt).
npm package vue framework

vue (@vue/cli) — Legacy Vue project scaffolder

The legacy @vue/cli command-line tool for scaffolding and serving Vue projects — deprecated in favour of create-vue + Vite, retained as reference for existing apps.
vue vue-cli scaffolding deprecated

W

wevtutil — Windows Event Log Manager

Query, export, clear, and manage Windows Event Log channels from the command line — the primary CLI for event log automation, log archiving, and scripted log analysis on Windows.
wevtutil windows cli scripting

whoami — Current User Identity

Display the current user name, SID, group memberships, and privileges from the Windows command prompt — essential for auditing security context in scripts and support scenarios.
whoami windows cli scripting

Windows Terminal — Profiles, Keybindings, Schemes

Configure Windows Terminal — settings.json structure, profiles for pwsh/cmd/wsl/ssh, keybindings, colour schemes, panes, and the wt.exe CLI.
terminal productivity customization windows

winston — Multi-Transport Logger for Node

Package-level reference for winston on npm — transports, formats, levels, daily rotation, and production patterns.
npm package winston logging

wmic — Windows Management Instrumentation CLI

Query and manage Windows system information — hardware, software, processes, services, and more — from the command prompt using WMI classes and WMIC's SQL-like syntax.
wmic windows cli scripting

wrangler — Cloudflare Workers CLI

Cloudflare's official CLI for building, configuring, and deploying Workers, Pages, KV, R2, D1, Vectorize, Hyperdrive, Queues, Workflows, and Secrets.
wrangler cloudflare workers cli

wrangler — Cloudflare Workers CLI

Package-level reference for the wrangler CLI on npm — install, Node support, transitive dependency footprint, and platform-binding gotchas.
npm package wrangler cloudflare

wsl — Managing Linux Distros from the wsl.exe CLI

Install, list, export, import, configure, and clone WSL distributions using the wsl.exe command on Windows 10 and 11.
wsl linux virtualization cli

X

xattr — Extended Attributes on macOS

Deep-dive on macOS extended attributes — listing, reading, writing, and removing xattrs with xattr(1); the Gatekeeper com.apple.quarantine flag; Spotlight metadata attributes; ACLs via ls -le and chmod +a; preserving attributes on copy with cp -p and rsync -X.
xattr macos cli filesystem

xcopy — Extended Copy

Copy files and directory trees with attribute preservation, date filtering, exclusion lists, and verification. The step between copy and robocopy for most scripting needs.
xcopy windows cli filesystem

Z

z/OS FTP Reference

FTP from TSO, batch FTP via JCL, SITE parameters, transfer modes, FTPS, FTP.DATA configuration, and JES spool transfers.
ftp zos mainframe networking

z/OS TCP/IP — NETSTAT, PING, Profile, and Diagnostics

Drive the z/OS Communications Server TCP/IP stack — NETSTAT variants, PING, TRACERTE, RESOLVE, PROFILE.TCPIP configuration, OMPROUTE, and SSH from z/OS UNIX, with end-to-end troubleshooting recipes.
zos mainframe tcpip networking

Zod — TypeScript-first schema validation with static type inference

TypeScript-first runtime validation library. Define schemas, validate inputs, infer static types — works at API boundaries, env config, forms, and tRPC.
javascript typescript zod validation

Zowe CLI — Modern z/OS DevOps from your laptop

Open-source command-line bridge into z/OS — manage datasets, jobs, USS files, consoles, TSO, and Db2 from Mac/Linux/Windows over z/OSMF or RSE-API.
zowe zos mainframe devops
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