A dense field notebook for operators
The Book of Secret Knowledge is a curated resource index for people who live around shells, networks, web services, Linux and BSD systems, security tooling, and operational debugging. It is not a book in the usual sense. It is a large README that gathers tools, manuals, cheat sheets, search engines, shell snippets, security references, and links the maintainer found useful in daily work.
That makes it different from a generic awesome list. sindresorhus/awesome is a directory of directories. The Book of Secret Knowledge is closer to an operator’s notebook: CLI tools, web tools, network utilities, DNS and HTTP references, SSL resources, system services, container links, hardening notes, penetration testing links, daily news sources, and shell one-liners live in one long document. The result is messy in the way a useful desk can be messy. You do not read it front to back. You search inside it when you need a tool name, a category, or a reminder that some diagnostic trick exists.
The README says the audience is broad, but then narrows it honestly: system and network administrators, DevOps engineers, pentesters, and security researchers. That is the right lens. A frontend developer may find interesting tools here. An operator is more likely to find something they can use the same day.
What is actually inside
The top-level sections cover CLI tools, GUI tools, web tools, systems and services, networks, containers and orchestration, manuals and tutorials, inspiring lists, blogs and videos, hacking and penetration testing, daily knowledge sources, other cheat sheets, shell one-liners, shell tricks, and shell functions.
The CLI section alone spans shells, plugins, file managers, terminal multiplexers, editors, network tools, DNS tools, HTTP tools, SSL, auditing tools, diagnostics, log analyzers, databases, Tor, messaging clients, productivity, and more. Web tools include SSL and security checkers, HTTP header linters, DNS utilities, mail tools, encoders, net tools, privacy links, code parsers, performance tools, search engines for Internet-scale scanning, password tools, CVE databases, exploit databases, mobile app scanners, and secure webmail. Other chapters move into operating systems, services, security hardening, labs, containers, tutorials, and curated reading.
This breadth is the value. It is also the main weakness. A directory this broad cannot guarantee that every linked service, exploit reference, scanner, or tutorial remains current. The README explicitly says URLs marked with an asterisk are temporarily unavailable and should not be deleted until permanent expiry is confirmed. That rule is more revealing than it looks. Link rot is expected, so the project treats temporary failure as a maintenance state rather than an instant removal signal.
How to use it well
Use it as a retrieval layer, not a checklist. If you need HTTP testing tools, search the README for HTTP. If you are auditing DNS posture, jump to DNS and passive DNS resources. If you are on a terminal and need a reminder of shell tricks, use the one-liners and functions sections as prompts, then verify any command before running it.
There is nothing to install from this repo. Clone it only if you want local search, offline access, or a base for contributing. The normal user action is to open the README, search by category, inspect a link, then leave the repo.
For security topics, add a second rule: treat links as starting points, not authority. A tool listed here can be useful and still outdated. An exploit database link can be educational without applying to your target. A hardening guide can be right for one environment and wrong for another. The repo is strongest when it reminds you what to investigate next.
Maintenance signals
As of 2026-06, the local data snapshot shows more than 227,000 stars and more than 13,000 forks. The star curve is long and heavy: it starts in 2018 and reaches a large audience by 2026. That popularity tells you the list resonated with operators and security learners.
The freshness signal is more mixed. The repository is not archived and was pushed in 2024. Issues are disabled, even though the data snapshot still reports historical issue counts. The latest visible merged pull requests through GitHub are from 2022, including additions such as Hurl, dnstwist, vaultwarden, TLS tools, and link cleanup. That does not make the list useless. It means you should not use it as a current inventory of best-in-class security tooling without checking each item.
The contribution guide reinforces that point. It asks contributors to avoid personal support in the issue tracker, explain problems and solutions in pull requests, and includes a small shell loop for finding broken links in README anchors. The repo’s own maintenance model assumes a long document that needs periodic pruning.
Comparison with nearby resource repos
| Repository | Stars | Scope | Best use | Main caveat |
|---|---|---|---|---|
| trimstray/the-book-of-secret-knowledge | 227,737 | Operator and security resource notebook | Find tools, manuals, cheat sheets, and diagnostics by category | Large link surface, so freshness varies |
| sindresorhus/awesome | 474,738 | Index of awesome lists | Jump to a topic-specific curated list | One level removed from the actual resources |
| awesome-selfhosted/awesome-selfhosted | 298,484 | Self-hosted services catalog | Choose software to run on your own servers | Narrower than a general operations notebook |
| jlevy/the-art-of-command-line | 161,278 | Command-line guidance in one page | Learn shell habits and Unix command-line practice | Less broad across security and infrastructure tools |
Counts are GitHub snapshots from 2026-06. The choice is about depth of intent. Use awesome when you need a topic gateway. Use awesome-selfhosted/awesome-selfhosted when you are choosing a service to host. Use The Book of Secret Knowledge when you need an operations and security grab bag with enough breadth to trigger memory.
Where it is strong
The repo is strong at category recall. You may know that a tool for passive DNS, HTTP header inspection, DNS performance testing, packet capture, terminal multiplexing, or CVE lookup exists, but not remember its name. This README often gets you from vague memory to candidate list quickly.
It is also strong for onboarding people into the tool landscape. A junior sysadmin or security learner can skim the table of contents and see the terrain: shells, networking, SSL, diagnostics, hardening, containers, tutorials, scanning, password handling, privacy tools, and daily reading. That map can be more useful than a lecture because it shows how wide the operational toolbox is.
Where it is weak
The repo is weak as a source of truth. Security tools age. Cloud defaults change. Web services shut down. Some tools are safe in a lab and risky in production. Some scanner names become outdated, moved, or replaced. A README list cannot carry that context for every entry.
It is also not a compliance document. Do not use it to decide whether an environment is secure. Use it to discover references, then validate against vendor docs, current advisories, your organization’s policy, and the legal boundaries of your test.
Related
For a broad list of lists, see sindresorhus/awesome. For self-hosted services and infrastructure software, see awesome-selfhosted/awesome-selfhosted. For kernel source and low-level systems context, torvalds/linux is the better primary source. For API discovery rather than operations tooling, public-apis/public-apis is the closer match.
FAQ
Is The Book of Secret Knowledge a course? No. It is a curated README of links, tools, manuals, cheat sheets, one-liners, and references. It has no lesson order or exercises.
Do I need to install anything from this repo? No. There is no package. Browse the README, search for a category, and follow the external link you need.
Is it still maintained? It is not archived and was pushed in 2024, but visible merged PR activity is older. Treat it as a useful mature directory, then verify individual tools and links before relying on them.
Is it safe to use for pentesting? The repo contains security and penetration testing references. Use them only in authorized environments, and treat each linked tool’s documentation and legal context as the authority.
How is it different from sindresorhus/awesome? awesome is a gateway to many topic lists. The Book of Secret Knowledge is a single operations-heavy notebook with direct links across sysadmin, DevOps, network, web, and security categories.