LLM-driven systems that pursue a goal by interleaving reasoning, tool calls, and observations inside a loop — and that decide for themselves which step to take next.
A versioned contract between two pieces of software — endpoints, verbs, payload shapes, errors, and auth — that decouples a caller from an implementation.
Non-blocking concurrency built on event loops, futures, promises, and coroutines that lets a single thread overlap many in-flight I/O operations.
The hierarchical, cached, globally-distributed naming system that turns human-readable hostnames into IP addresses, mail routes, service endpoints, and trust anchors.
The OS-layer abstraction that turns a flat block device into named, permissioned, hierarchical files — covering inodes, paths, permissions, journaling, and copy-on-write.
The request/response protocol that carries almost every API, page, and download on the modern internet — methods, status codes, headers, caching, and three wire formats (HTTP/1.1, HTTP/2, HTTP/3).
Text-based data interchange format derived from JavaScript object literals and standardised as RFC 8259 / ECMA-404.
An operating-system primitive that streams one process's stdout into another's stdin, letting small composable tools build large data flows.
A pattern-matching mini-language for searching, validating, and rewriting text — implemented (with subtly different dialects) by every modern language and CLI tool.
Grounding LLM responses in chunks retrieved from an external corpus so the model reasons over real, citable sources instead of parametric memory alone.
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.
Prevent display, idle, system, or user-active sleep for the duration of a command, a fixed time, or a process — without permanently changing pmset.
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.
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.
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.
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.
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.
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.
Comprehensive macOS terminal reference covering file management, processes, networking, Homebrew, defaults, diskutil, launchctl, pbcopy/pbpaste, open, say, and power-user recipes.
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.
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.
Drive macOS GUI apps, system events, dialogs, notifications, and Finder from the terminal using AppleScript or JavaScript for Automation (JXA).
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.
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 built-in image processor covering format conversion, resizing, cropping, rotation, color profiles, metadata inspection, and batch processing recipes.
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.
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.
Drive Time Machine backups, destinations, exclusions, local APFS snapshots, restores, and verification entirely from the terminal — without opening System Settings.
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.
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.
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.
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.
Importing, tagging, querying, and organizing a music library with beets — config, plugins, queries, and common workflows on Windows.
Navigate the Windows command prompt's current working directory. Covers drive switching, absolute and relative paths, UNC paths, and path-with-spaces quoting.
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.
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.
Install, upgrade, pin, and script software installs on Windows with the choco CLI, packages.config files, and custom sources.
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.
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.
Analyze, defragment, and optimize volumes from the command line — consolidate free space on HDDs, issue TRIM on SSDs, and schedule or review optimization tasks.
Delete one or more files from the Windows command prompt. Covers wildcards, quiet mode, attribute overrides, recursive deletion patterns, and the distinction from rmdir.
Display files and folders in a directory with filtering, sorting, formatting, and recursive traversal options. The Windows cmd.exe equivalent of Unix ls.
Create, delete, format, extend, shrink, and assign drive letters to disk partitions from the Windows command prompt using an interactive or scripted REPL interface.
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.
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.
Print text to stdout, expand environment variables, write blank lines, redirect output to files, and toggle command-echoing in cmd.exe batch scripts.
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.
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.
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.
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.
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.
Display the DNS hostname of the local Windows machine from the command prompt — useful in scripts to identify the machine without parsing systeminfo output.
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.
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.
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.
Create one or more directories from the Windows command prompt. Covers single and nested directory creation, batch patterns, and common scripting idioms.
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.
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.
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.
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.
Configure network interfaces, firewall rules, wireless profiles, port proxies, and Winsock settings from an elevated command prompt — the comprehensive Windows network configuration CLI.
Display active TCP/UDP connections, listening ports, routing tables, interface statistics, and per-connection process IDs from the Windows command prompt.
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.
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.
Send ICMP echo requests to a host to test reachability, measure round-trip latency, and detect packet loss from the Windows command prompt.
Manage Windows power plans, enable or disable hibernation, diagnose battery health and sleep failures, and generate energy efficiency reports from the command prompt.
Variables, operators, pipelines, Where-Object, ForEach-Object, Select-Object, sorting, grouping, remoting, jobs, CIM, registry, JSON, error handling, and common cmdlets.
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.
Master terminating vs non-terminating errors, $ErrorActionPreference, try/catch/finally, throw vs Write-Error, transcripts, and strict mode.
Install, discover, update, and author PowerShell modules: PowerShellGet, PSResourceGet, the Gallery, $PSModulePath, $PROFILE customisation, PSReadLine, SecretManagement, and the must-have module shortlist.
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.
Execute PowerShell against one or many remote hosts using WinRM or SSH transport, persistent sessions, credential management, and JEA.
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.
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.
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.
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.
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.
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.
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.
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.
Install dev tools without admin rights using Scoop — buckets, manifests, multi-version installs, and reproducible setups.
Set, display, and delete cmd.exe environment variables within the current session, perform integer arithmetic with /A, and read interactive user input with /P.
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.
Connect to remote hosts, transfer files, and forward ports over an encrypted channel using the OpenSSH client built into Windows 10 and later.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Configure Windows Terminal — settings.json structure, profiles for pwsh/cmd/wsl/ssh, keybindings, colour schemes, panes, and the wt.exe CLI.
Installing, upgrading, and managing packages with Windows Package Manager.
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.
Install, list, export, import, configure, and clone WSL distributions using the wsl.exe command on Windows 10 and 11.
Running Linux tools from Windows and vice versa, file system access, and networking between WSL and Windows.
Copy files and directory trees with attribute preservation, date filtering, exclusion lists, and verification. The step between copy and robocopy for most scripting needs.
Downloading video and audio from YouTube and hundreds of other sites with yt-dlp — formats, playlists, subtitles, post-processing, and config.
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.
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.
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.
IBM DFSORT control statements and ICETOOL operators for sorting, merging, joining, and reshaping batch datasets on z/OS.
FTP from TSO, batch FTP via JCL, SITE parameters, transfer modes, FTPS, FTP.DATA configuration, and JES spool transfers.
Define, reference, and clean up z/OS generation data groups via IDCAMS — relative generations, rollover behaviour, model DSCBs, and the modern GDGEXTENDED mode.
Define, copy, list, alter, and delete VSAM clusters and general datasets — the everyday utility for catalog and dataset lifecycle on z/OS.
IBM utility for copying, merging, compressing, unloading, and reloading PDS and PDSE libraries on z/OS, including member selection, rename, and exclusion.
Deep dive into the ISPF editor — primary commands, line commands, BNDS/CC/MM column edits, ISREDIT macro services, profile management, and recovery.
Comprehensive reference for the JCL DD statement: DSN, DISP, DCB, SPACE, UNIT, VOL=SER, concatenation, DUMMY, SYSOUT, KEYLEN.
Job Control Language syntax, common statements, EXEC, DD, and SYSOUT patterns.
z/OS Job Entry Subsystem 2 operator slash-commands for jobs, initiators, output, classes, NJE, and spool — from the console and from SDSF.
TSO commands for RACF user, group, dataset, and general-resource profile administration on z/OS.
Practical REXX patterns for z/OS automation, TSO commands, and ISPF services.
Browse, filter, and act on JES2 spool from inside ISPF — find your job, read SYSOUT, cancel, purge, and issue operator commands.
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.
Complete ISPF menu options, primary commands, line commands, edit profile, utilities, DSLIST, SDSF, TSO commands, RACF, and keyboard shortcuts.
The UNIX side of z/OS — OMVS, ISHELL, oedit, BPXBATCH, file tagging, zFS, and bridging shell scripts to MVS batch.
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.
Debian and Ubuntu package management — update, install, remove, upgrade, and maintain packages with apt-get.
Fast, multi-protocol download utility supporting HTTP(S), FTP, SFTP, BitTorrent, and Metalink with resumption and parallel connections.
Pattern-action language for structured text. Field splitting, built-in variables, arithmetic, string functions, arrays, BEGIN/END blocks, and practical data-processing recipes.
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.
A cat clone with syntax highlighting, Git integration, line numbers, paging, and diff support. Drop-in replacement with many quality-of-life improvements for viewing files in the terminal.
Time-based job scheduler on Unix. Covers crontab syntax, user vs. system crontabs, environment quirks, logging, anacron, and the modern systemd timer alternative.
Transfer data with URLs. Covers HTTP methods, headers, authentication, forms, TLS, cookies, proxies, timeouts, parallel downloads, and a comprehensive recipe collection.
Extract columns by delimiter or byte position (cut), merge files column-wise (paste), and join on a common key field (join). Essential for tab/CSV/field-delimited data.
Check filesystem free space (df), measure directory sizes (du), and view a colourful disk overview (duf). Covers all key flags, human-readable output, modern alternatives (dust, gdu, ncdu), and common sysadmin recipes.
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.
A modern ls replacement with colour coding, Git status, icons, tree view, and rich metadata. eza is the actively maintained fork of the original exa project.
Modern find replacement written in Rust. Simpler syntax, respects .gitignore, supports regex and glob patterns, parallel execution, and coloured output.
Comprehensive FFmpeg reference covering transcoding, container conversion, scaling, filters, audio, subtitles, streaming, batch processing, and ffplay — with NVIDIA NVENC/NVDEC/CUDA alternatives, Vulkan compute codecs, VVC/H.266 decoding, and the FFmpeg 8.0 Whisper filter.
Comprehensive ffprobe reference for inspecting media files — formats, streams, frames, packets, chapters, metadata — with output formats (default, json, csv, xml, flat, ini), select_streams, show_entries, and one-liners for duration, fps, codec, resolution, and bitrate.
Comprehensive fish shell reference covering syntax, variables, functions, abbreviations, completions, config files, path management, prompt customization, Fisher plugins, fish 4.x features (Rust rewrite), and migration from bash/zsh.
Interactive fuzzy finder for the terminal. Covers key bindings, shell integration, previews with bat and tree, multi-select, popup/tmux mode, --listen IPC, and pipelines with git, kill, and vim.
Complete GitHub CLI reference. Auth, configuration, repos, issues, pull requests, releases, Actions, attestations, projects, models, rulesets, caches, secrets, gists, search, API, extensions, and codespaces.
Complete Git reference. Setup, staging, committing, branching, merging, rebasing, stashing, remotes, tags, log inspection, undoing mistakes, submodules, and power-user aliases.
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.
Search files and streams using fixed strings, extended regex, or PCRE. Covers all major flags, context, recursive search, and pipeline patterns.
Interactive process and resource monitor for the terminal. Covers function keys, sorting, filtering, signal sending, tree view, threads, and how to read load averages and memory correctly. Compares with top, btop, and bottom.
Comprehensive ImageMagick 7 reference covering magick, identify, mogrify, composite, montage, format conversion, resize, crop, rotate, color adjustments, effects, drawing, text, PDF operations, policy.xml hardening, and batch processing.
Modern replacement for ifconfig, route, and arp. Inspect and configure interfaces, addresses, routes, neighbour tables, and network namespaces with the iproute2 ip command.
Query and follow systemd's structured journal. Covers unit filters, time ranges, priority levels, boot logs, namespaces, invocations, output formats, persistence, configuration, and disk-vacuum.
Slice, filter, map, and transform JSON data from the command line. Covers all essential filters, built-in functions, select, map, reduce, streaming, jq 1.7/1.8 additions, and real-world API response processing.
Diagnose what's holding a port, which files a process has open, and the state of every TCP/UDP socket using lsof and the modern iproute2 ss utility.
Practical Makefile patterns: targets, prerequisites, automatic variables, pattern rules, parallel builds, and a working lint/test/build/clean workflow for any project.
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.
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.
Inspect running processes (ps), list network connections and listening ports (ss / netstat). Covers output formats, filtering, process trees, and socket state analysis.
Comprehensive reference for qsv: count, headers, stats, moarstats, select, search, sort, dedup, frequency, join, sqlp, luau, apply, schema, validate, sample, split, MCP server, and more — with examples and outputs.
Modern grep replacement written in Rust. Respects .gitignore, searches hidden files optionally, supports PCRE2, and is significantly faster on large codebases.
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.
Non-interactive text transformation. Substitution, deletion, insertion, address ranges, in-place editing, and multi-line patterns with practical recipes.
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.
Comprehensive SoX reference covering file info, format conversion, synthesis, playback, recording, combining, effects (trim, reverb, compand, rate, pitch, tempo, noise gate), batch processing, spectrograms, and piping.
Local, remote, and dynamic SSH tunnels — port forwarding, SOCKS proxies, jump hosts, ssh_config directives, agent forwarding, autossh persistence, post-quantum key exchange, and operational recipes.
Writing, enabling, and managing systemd service, timer, and socket units.
Bundle directory trees into a single archive file with optional compression. Covers create/extract/list, gzip/bzip2/xz formats, exclusions, transforms, and incremental backups.
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.
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.
Non-interactive network downloader. Covers single and batch downloads, recursive mirroring, authentication, resuming, rate limiting, and site archiving.
Extract data from HTML, XML, and JSON using XPath, CSS selectors, pattern matching, and JSONiq from the command line.
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