What it does
The Book of Secret Knowledge is a single massive README — 4,400 lines of curated links, shell one-liners, shell functions, cheatsheets, and tool catalogs, organized into chapters that cover CLI tools, networking, security, penetration testing, hacking, and daily knowledge sources.
Why I starred it
214,000 stars. That's roughly in the same range as freeCodeCamp, build-your-own-x, and the original awesome list. For a document repo with no code, no CLI, no API, that number means something specific: this is the kind of reference that someone has open in a tab at all times.
What separates it from the typical "awesome-X" list is the shell one-liners and shell functions sections. Most awesome lists are link dumps. This one has substantive executable content — one-liners that are actually non-obvious, shell functions you'd add to your .bashrc, and tricks that read like they were written by someone who spent years running servers and hit every one of these problems in production.
How it works
The README is organized into 15 chapters. The tool lists (CLI Tools, GUI Tools, Web Tools) follow a consistent structure:
<a href="https://github.com/sharkdp/fd"><b>fd</b></a> - is a simple, fast and user-friendly alternative to find.<br>
HTML inside markdown, which is deliberate — it lets the author control whitespace and indentation in a way that pure markdown doesn't allow at that density.
The structural decision to lean on raw HTML is the only real technical choice in the repo, and it's a pragmatic one. GitHub renders HTML inside markdown faithfully, so the dense indented lists with non-breaking spaces ( ) render cleanly without needing custom CSS or a static site generator.
The shell one-liners section is where the repo earns its reputation. These aren't ls -la alternatives — they're multi-step pipelines doing real work:
# Top 20 most-used commands in your shell history
history | \
awk '{CMD[$2]++;count++;}END { for (a in CMD)print CMD[a] " " CMD[a]/count*100 "% " a;}' | \
grep -v "./" | \
column -c3 -s " " -t | \
sort -nr | nl | head -n 20Or this, for sanitizing your bash history of credentials while keeping the session active:
function sterile() {
history | awk '$2 != "history" { $1=""; print $0 }' | egrep -vi "\
curl\b+.*(-E|--cert)\b+.*\b*|\
curl\b+.*--pass\b+.*\b*|\
curl\b+.*(-u|--user).*:.*\b*
.*(-H|--header).*(token|auth.*)\b+.*|\
wget\b+.*--.*password\b+.*\b*|\
http.?://.+:.+@.*\
" > $HOME/histbuff; history -r $HOME/histbuff;
}
export PROMPT_COMMAND="sterile"That pattern — hooking into PROMPT_COMMAND so it runs after every command — is the non-obvious part. Most people trying to solve this problem would write a history | grep | delete script they run manually. Wiring it into PROMPT_COMMAND means it's continuous, not a cleanup pass.
The shell functions chapter has ready-to-drop utilities. The DomainResolve function hits Google's DNS-over-HTTPS API directly and extracts the A record via jq:
function DomainResolve() {
local _host="$1"
_host_ip=$(curl --request GET -ks -m 15 \
"https://dns.google.com/resolve?name=${_host}&type=A" | \
jq '.Answer[0].data' | tr -d "\"" 2>/dev/null)
if [[ -z "$_host_ip" ]] || [[ "$_host_ip" == "null" ]]; then
echo -en "Unsuccessful domain name resolution.\\n"
else
echo -en "$_host > $_host_ip\\n"
fi
}Small, dependency-light (only curl and jq), and the error handling is explicit rather than letting a failed jq query silently produce garbage output.
The hacking and penetration testing chapter reads like the canonical starting point for someone setting up a pentest environment from scratch — Metasploit, Burp Suite, sqlmap, but also less-obvious choices like p0f for passive OS fingerprinting and yara for pattern matching against binary files.
Using it
There's no CLI. You read it. The most effective workflow is using GitHub's native search (/) to jump to a specific tool category, or cloning the repo and using grep:
git clone https://github.com/trimstray/the-book-of-secret-knowledge
grep -n "socat" README.md | head -20The one-liners section is indexed by tool name with anchor links, so linking to a specific section is reliable:
https://github.com/trimstray/the-book-of-secret-knowledge#tool-ssh
https://github.com/trimstray/the-book-of-secret-knowledge#tool-tcpdump
That linking structure is intentional. The table of contents inside each chapter is a manual HTML anchor list — fragile to maintain, but functional.
Rough edges
The last real commit with content was several years ago. Recent commits are cosmetic fixes, formatting changes, and the occasional merged PR. The "Add one-liners for collection tools" item has been in the TODO since the beginning and never shipped.
Some links are dead. The README acknowledges this with a * marker for temporarily unavailable URLs, but plenty of unmarked links 404 without warning. For a reference document that gets consulted in a pinch, hitting dead links is a real friction point.
The shell functions chapter is thin — only two functions (DomainResolve and GetASN). Given how strong the one-liners section is, this gap is noticeable. The TODO explicitly mentions adding useful shell functions, so this was on the author's radar, but it never happened.
The curation quality is uneven across chapters. The CLI tools section is tightly curated with brief, precise descriptions. The blogs and Twitter accounts sections feel like timestamp artifacts — links to accounts and blogs that may no longer be active or relevant.
Bottom line
This is a reference document, not a framework. If you work with Linux servers, run security audits, or spend significant time in the terminal, it's worth having bookmarked and searched before you go looking at Stack Overflow. The one-liners alone are worth the bookmark.