InternetServicesBook/README.md

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<h4 align="center">A collection of awesome lists, manuals, blogs, hacks, one-liners, cli/web tools and more.</h4>

<br>

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<div align="center">
  <sub>Created by
  <a href="https://twitter.com/trimstray">trimstray</a> and
  <a href="https://github.com/trimstray/the-book-of-secret-knowledge/graphs/contributors">
    contributors
  </a>
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<br>

***

## :notebook_with_decorative_cover: &nbsp;What is it?

This list is a collection of various materials that I use every day in my work. It contains a lot of useful information gathered in one piece.

## :restroom: &nbsp;For whom?

It is intended for everyone and anyone - especially for System and Network Administrators, DevOps, Pentesters or Security Researchers.

## :information_source: &nbsp;Contributing

A few simple rules for this project:

- inviting and clear
- not tiring
- useful

These below rules may be better:

- easy to contribute to (Markdown + HTML ...)
- easy to find (no TOC, maybe it's worth creating them?)

Url marked **\*** is temporary unavailable. Please don't delete it without confirming that it has permanently expired.

Before add pull request please see **[this](https://github.com/trimstray/the-book-of-secret-knowledge/blob/master/CONTRIBUTING.md)**. All **suggestions/PR** are welcome!

## :ballot_box_with_check: &nbsp;Todo

- [ ] Add useful shell functions
- [ ] Add one-liners for collection tools (eg. CLI Tools)
- [ ] Generate book pdf format

## :anger: &nbsp;The Book of Secret Knowledge (Chapters)

#### CLI Tools

##### :black_small_square: Shells

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://ohmyz.sh/"><b>Oh My ZSH!</b></a> - the best framework for managing your Zsh configuration.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/Bash-it/bash-it"><b>bash-it</b></a> - framework for using, developing and maintaining shell scripts and custom commands for your daily work.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/oh-my-fish/oh-my-fish"><b>Oh My Fish</b></a> - the Fishshell framework.<br>
</p>

##### :black_small_square: Managers

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://midnight-commander.org/"><b>Midnight Commander</b></a> - visual file manager, licensed under GNU General Public License.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.gnu.org/software/screen/"><b>screen</b></a> - full-screen window manager that multiplexes a physical terminal.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/tmux/tmux/wiki"><b>tmux</b></a> - terminal multiplexer, lets you switch easily between several programs in one terminal.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/dennishafemann/tmux-cssh"><b>tmux-cssh</b></a> - sets a comfortable and easy to use functionality, clustering and synchronizing virtual tmux-sessions.<br>
</p>

##### :black_small_square: Terminal emulators

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/Guake/guake"><b>Guake</b></a> - is a dropdown terminal made for the GNOME desktop environment.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://gnometerminator.blogspot.com/p/introduction.html"><b>Terminator</b></a> - is based on GNOME Terminal, useful features for sysadmins and other users.<br>
</p>

##### :black_small_square: Network

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://nmap.org/"><b>nmap</b></a> - free and open source (license) utility for network discovery and security auditing.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/robertdavidgraham/masscan"><b>masscan</b></a> - the fastest Internet port scanner, spews SYN packets asynchronously.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/gvb84/pbscan"><b>pbscan</b></a> - faster and more efficient stateless SYN scanner and banner grabber.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.hping.org/"><b>hping</b></a> - command-line oriented TCP/IP packet assembler/analyzer.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/traviscross/mtr"><b>mtr</b></a> - functionality of the 'traceroute' and 'ping' programs in a single network diagnostic tool.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://netcat.sourceforge.net/"><b>netcat</b></a> - networking utility which reads and writes data across network connections, using the TCP/IP protocol.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.tcpdump.org/"><b>tcpdump</b></a> - powerful command-line packet analyzer.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.wireshark.org/docs/man-pages/tshark.html"><b>tshark</b></a> - dump and analyze network traffic (wireshark cli).<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/jpr5/ngrep"><b>ngrep</b></a> - is like GNU grep applied to the network layer.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/tgraf/bmon"><b>bmon</b></a> - monitoring and debugging tool to capture networking related statistics and prepare them visually.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://iptraf.seul.org/2.6/manual.html#installation"><b>iptraf-ng</b></a> - is a console-based network monitoring program for Linux that displays information about IP traffic.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://iperf.fr/"><b>iPerf3</b></a> - is a tool for active measurements of the maximum achievable bandwidth on IP networks.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/Microsoft/Ethr"><b>ethr</b></a> - is a Network Performance Measurement Tool for TCP, UDP & HTTP.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/troglobit/nemesis"><b>Nemesis</b></a> - packet manipulation CLI tool; craft and inject packets of several protocols.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/packetfu/packetfu"><b>packetfu</b></a> - a mid-level packet manipulation library for Ruby.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://scapy.net/"><b>Scapy</b></a> - packet manipulation library; forge, send, decode, capture packets of a wide number of protocols.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://aria2.github.io/"><b>aria2</b></a> - is a lightweight multi-protocol & multi-source command-line download utility.<br>
</p>

##### :black_small_square: Network (DNS)

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/mschwager/fierce"><b>fierce</b></a> - a DNS reconnaissance tool for locating non-contiguous IP space.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/aboul3la/Sublist3r"><b>sublist3r</b></a> - fast subdomains enumeration tool for penetration testers.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/OWASP/Amass"><b>amass</b></a> - tool obtains subdomain names by scraping data sources, crawling web archives and more.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/google/namebench"><b>namebench</b></a> - provides personalized DNS server recommendations based on your browsing history.<br>
</p>


##### :black_small_square: Network (HTTP)

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://curl.haxx.se/"><b>Curl</b></a> - command line tool and library for transferring data with URLs.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://gitlab.com/davidjpeacock/kurly"><b>kurly</b></a> - is an alternative to the widely popular curl program, written in Golang.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/jkbrzt/httpie"><b>HTTPie</b></a> - a user-friendly HTTP client.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/asciimoo/wuzz"><b>wuzz</b></a> - interactive cli tool for HTTP inspection.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/trimstray/htrace.sh"><b>htrace.sh</b></a> - shell script to debugging http/https; ssllabs, mozilla observatory, testssl.sh and nmap nse support.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/reorx/httpstat"><b>httpstat</b></a> - visualizes curl statistics in a way of beauty and clarity.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://lynx.browser.org/"><b>Lynx</b></a> - is a text browser for the World Wide Web.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.joedog.org/siege-home/"><b>siege</b></a> - is an http load testing and benchmarking utility.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/wg/wrk"><b>wrk</b></a> - is a modern HTTP benchmarking tool capable of generating significant load.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/codesenberg/bombardier"><b>bombardier</b></a> - fast cross-platform HTTP benchmarking tool written in Go.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/cmpxchg16/gobench"><b>gobench</b></a> - http/https load testing and benchmarking tool.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/OJ/gobuster"><b>gobuster</b></a> - free and open source directory/file & DNS busting tool written in Go<br>
</p>

##### :black_small_square: SSL/Security

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.openssl.org/"><b>openssl</b></a> - is a robust, commercial-grade, and full-featured toolkit for the TLS and SSL protocols.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://gnutls.org/manual/html_node/gnutls_002dcli-Invocation.html"><b>gnutls-cli</b></a> - client program to set up a TLS connection to some other computer.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/nabla-c0d3/sslyze"><b>sslyze
</b></a> - fast and powerful SSL/TLS server scanning library.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/rbsec/sslscan"><b>sslscan</b></a> - tests SSL/TLS enabled services to discover supported cipher suites.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/drwetter/testssl.sh"><b>testssl.sh</b></a> - testing TLS/SSL encryption anywhere on any port.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.tarsnap.com/spiped.html"><b>spiped</b></a> - is a utility for creating symmetrically encrypted and authenticated pipes between socket addresses.<br>
</p>

##### :black_small_square: Auditing Tools

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://cisofy.com/lynis/"><b>Lynis</b></a> - battle-tested security tool for systems running Linux, macOS, or Unix-based operating system.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/rebootuser/LinEnum"><b>LinEnum</b></a> - scripted Local Linux Enumeration & Privilege Escalation Checks.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/installation/rkhunter"><b>Rkhunter</b></a> - scanner tool for Linux systems that scans backdoors, rootkits and local exploits on your systems.<br>
</p>

##### :black_small_square: System Diagnostics/Debuggers

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/strace/strace"><b>strace</b></a> - diagnostic, debugging and instructional userspace utility for Linux.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://dtrace.org/blogs/about/"><b>DTrace</b></a> - is a performance analysis and troubleshooting tool.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://en.wikipedia.org/wiki/Ltrace"><b>ltrace</b></a> - is a library call tracer, used to trace calls made by programs to library functions.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/draios/sysdig"><b>sysdig</b></a> - system exploration and troubleshooting tool with first class support for containers.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://nicolargo.github.io/glances/"><b>glances</b></a> - cross-platform system monitoring tool written in Python.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/hishamhm/htop"><b>htop</b></a> - interactive text-mode process viewer for Unix systems. It aims to be a better 'top'.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.atoptool.nl/"><b>atop</b></a> - ASCII performance monitor. Includes statistics for CPU, memory, disk, swap, network, and processes.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://en.wikipedia.org/wiki/Lsof"><b>lsof</b></a> - displays in its output information about files that are opened by processes.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.brendangregg.com/flamegraphs.html"><b>FlameGraph</b></a> - stack trace visualizer.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/zevv/lsofgraph"><b>lsofgraph</b></a> - small utility to convert Unix lsof output to a graph showing FIFO and UNIX interprocess communication.<br>

</p>

##### :black_small_square: Log Analyzers

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://goaccess.io/"><b>GoAccess</b></a> - real-time web log analyzer and interactive viewer that runs in a terminal.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/lebinh/ngxtop"><b>ngxtop</b></a> - real-time metrics for nginx server.<br>
</p>

##### :black_small_square: Databases

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/xo/usql"><b>usql</b></a> - universal command-line interface for SQL databases.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/dbcli/pgcli"><b>pgcli</b></a> - postgres CLI with autocompletion and syntax highlighting.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/dbcli/mycli"><b>mycli</b></a> - terminal client for MySQL with autocompletion and syntax highlighting.<br>
</p>

##### :black_small_square: TOR

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/GouveaHeitor/nipe"><b>Nipe</b></a> - script to make Tor Network your default gateway.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/trimstray/multitor"><b>multitor</b></a> - a tool that lets you create multiple TOR instances with a load-balancing.<br>
</p>

##### :black_small_square: Other

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://inotify.aiken.cz/"><b>incron</b></a> - is an inode-based filesystem notification technology.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/tldr-pages/tldr"><b>tldr</b></a> - simplified and community-driven man pages.<br>
</p>

#### GUI Tools

##### :black_small_square: Network

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.wireshark.org/"><b>Wireshark</b></a> - is the world’s foremost and widely-used network protocol analyzer.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.torproject.org/projects/torbrowser.html.en"><b>TOR Browser</b></a> - protect your privacy and defend yourself against network surveillance and traffic analysis.<br>
</p>

##### :black_small_square: Password Managers

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://keepassxc.org/"><b>KeePassXC</b></a> - store your passwords safely and auto-type them into your everyday websites and apps.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.enpass.io/"><b>Enpass</b></a> - password manager and secure wallet.<br>
</p>

##### :black_small_square: Text editors

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.sublimetext.com/3"><b>Sublime Text</b></a> - is a lightweight, cross-platform code editor known for its speed, ease of use.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://code.visualstudio.com/"><b>Visual Studio Code</b></a> - an open-source and free source code editor developed by Microsoft.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://atom.io/"><b>Atom</b></a> - a hackable text editor for the 21st Century.<br>
</p>

#### Web Tools

##### :black_small_square: SSL/Security

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.ssllabs.com/ssltest/"><b>SSL Server Test</b></a> - free online service performs a deep analysis of the configuration of any SSL web server.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://dev.ssllabs.com/ssltest/"><b>SSL Server Test (DEV)</b></a> - free online service performs a deep analysis of the configuration of any SSL web server.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.htbridge.com/ssl/"><b>ImmuniWeb® SSLScan</b></a> - test SSL/TLS (PCI DSS, HIPAA and NIST).<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.jitbit.com/sslcheck/"><b>SSL Check</b></a> - scan your website for non-secure content.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://urlscan.io/"><b>urlscan.io</b></a> - service to scan and analyse websites.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://report-uri.com/home/tools"><b>Report URI</b></a> - monitoring security policies like CSP and HPKP.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://csp-evaluator.withgoogle.com/"><b>CSP Evaluator</b></a> - allows developers and security experts to check if a Content Security Policy.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://uselesscsp.com/"><b>Useless CSP</b></a> - public list about CSP in some big players (might make them care a bit more).<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://whynohttps.com/"><b>Why No HTTPS?</b></a> - list of the world's top 100 websites by Alexa rank not automatically redirecting insecure requests.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://cipherli.st/"><b>cipherli.st</b></a> - strong ciphers for Apache, Nginx, Lighttpd and more.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://badssl.com/"><b>badssl.com</b></a> - memorable site for testing clients against bad SSL configs.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://tlsfun.de/"><b>tlsfun.de</b></a> - registered for various tests regarding the TLS/SSL protocol.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://ccadb.org/resources"><b>Common CA Database</b></a> - repository of information about CAs, and their root and intermediate certificates.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://certstream.calidog.io/"><b>CERTSTREAM</b></a> - real-time certificate transparency log update stream.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://crt.sh/"><b>crt.sh</b></a> - discovers certificates by continually monitoring all of the publicly known CT.<br>
</p>

##### :black_small_square: Browsers

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://caniuse.com/#home"><b>Can I use</b></a> - provides up-to-date browser support tables for support of front-end web technologies.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://panopticlick.eff.org/"><b>Panopticlick 3.0</b></a> - is your browser safe against tracking?<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://privacy.net/analyzer/"><b>Privacy Analyzer</b></a> - see what data is exposed from your browser.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://browserleaks.com/"><b>Web Browser Security</b></a> -  it's all about Web Browser fingerprinting.<br>
</p>

##### :black_small_square: Privacy

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.privacytools.io/"><b>privacytools.io</b></a> - provides knowledge and tools to protect your privacy against global mass surveillance.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://dnsprivacy.org/wiki/display/DP/DNS+Privacy+Test+Servers"><b>DNS Privacy Test Servers</b></a> - DNS privacy recursive servers list (with a 'no logging' policy).<br>
</p>

##### :black_small_square: HTTP Headers

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://securityheaders.com/"><b>Security Headers</b></a> - analyse the HTTP response headers (with rating system to the results).<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://observatory.mozilla.org/"><b>Observatory by Mozilla</b></a> - set of tools to analyze your website.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://enable-cors.org/index.html"><b>Enable CORS</b></a> - enable cross-origin resource sharing.<br>
</p>

##### :black_small_square: DNS

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://viewdns.info/"><b>ViewDNS</b></a> - one source for free DNS related tools and information.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://dnslytics.com/"><b>DNSlytics</b></a> - online investigation tool.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://dnsspy.io/"><b>DNS Spy</b></a> - monitor, validate and verify your DNS configurations.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://findsubdomains.com/"><b>Find subdomains online</b></a> - find subdomains for security assessment penetration test.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://dnsdumpster.com/"><b>DNSdumpster</b></a> - dns recon & research, find & lookup dns records.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://dnstable.com/"><b>DNS Table online</b></a> - search for DNS records by domain, IP, CIDR, ISP.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://ptrarchive.com/"><b>PTRarchive.com</b></a> - this site is responsible for the safekeeping of historical reverse DNS records.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://xip.io/"><b>xip.ip</b></a> - wildcard DNS for everyone.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://intodns.com/"><b>intoDNS</b></a> - DNS and mail server health checker.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://leafdns.com/"><b>Leaf DNS</b></a> - comprehensive DNS tester.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://ceipam.eu/en/dnslookup.php"><b>dnslookup (ceipam)</b></a> - one of the best DNS propagation checker (and not only).<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://whatsmydns.com"><b>What's My DNS</b></a> - DNS propagation checking tool.<br>

</p>

##### :black_small_square: Mail

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://mxtoolbox.com/SuperTool.aspx"><b>MX Toolbox</b></a> - all of your MX record, DNS, blacklist and SMTP diagnostics in one integrated tool.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.blacklistalert.org/"><b>blacklistalert</b></a> - checks to see if your domain is on a Real Time Spam Blacklist.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://multirbl.valli.org/"><b>MultiRBL</b></a> - complete IP check for sending Mailservers.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://dkimvalidator.com/"><b>DKIM SPF & Spam Assassin Validator</b></a> - checks mail authentication and scores messages with Spam Assassin.<br>
</p>

##### :black_small_square: Net-tools

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://toolbar.netcraft.com/site_report"><b>Netcraft</b></a> - detailed report about the site, helping you to make informed choices about their integrity.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.ripe.net/"><b>RIPE NCC</b></a> - not-for-profit membership association, a Regional Internet Registry and the secretariat for the RIPE.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.robtex.com/"><b>Robtex</b></a> - uses various sources to gather public information about IP numbers, domain names, host names, routes etc.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://securitytrails.com/"><b>Security Trails</b></a> - APIs for Security Companies, Researchers and Teams.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://tools.keycdn.com/curl"><b>Online Curl</b></a> - curl test, analyze HTTP Response Headers.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://ping.eu/"><b>Ping.eu</b></a> - online Ping, Traceroute, DNS lookup, WHOIS and others.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://network-tools.com/"><b>Network-Tools</b></a> - network tools for webmasters, IT technicians & geeks.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.url-encode-decode.com/"><b>URL Encode/Decode</b></a> - tool from above to either encode or decode a string of text.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://uncoder.io/"><b>Uncoder</b></a> - the online translator for search queries on log data.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://regexr.com/"><b>RegExr</b></a> - online tool to learn, build, & test Regular Expressions (RegEx / RegExp).<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.hardenize.com/"><b>Hardenize</b></a> - deploy the security standards.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.virustotal.com/#/home/upload"><b>VirusTotal</b></a> - analyze suspicious files and URLs to detect types of malware.<br>
</p>

##### :black_small_square: Code parsers/playgrounds

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.shellcheck.net/"><b>ShellCheck</b></a> - finds bugs in your shell scripts.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://explainshell.com/"><b>explainshell</b></a> - get interactive help texts for shell commands.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://jsbin.com/?html,output"><b>jsbin</b></a> - live pastebin for HTML, CSS & JavaScript and more.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://sandbox.onlinephpfunctions.com/"><b>PHP Sandbox</b></a> - test your PHP code with this code tester.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.repl.it/"><b>Repl.it</b></a> - an instant IDE to learn, build, collaborate, and host all in one place.<br>
</p>

##### :black_small_square: Performance

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://gtmetrix.com/"><b>GTmetrix</b></a> - analyze your site’s speed and make it faster.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://performance.sucuri.net/"><b>Sucuri loadtimetester</b></a> - test here the
performance of any of your sites from across the globe.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://tools.pingdom.com/"><b>Pingdom Tools</b></a> - analyze your site’s speed around the world.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://developers.google.com/speed/pagespeed/insights/"><b>PageSpeed Insights</b></a> - analyze your site’s speed and make it faster.<br>
</p>

##### :black_small_square: Mass scanners (search engines)

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://censys.io/"><b>Censys</b></a> - platform that helps information security practitioners discover, monitor, and analyze devices.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.shodan.io/"><b>Shodan</b></a> - the world's first search engine for Internet-connected devices.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://2000.shodan.io/#/"><b>Shodan 2000</b></a> - if you use Shodan for everyday work, be sure to see it - looks for randomly generated data from Shodan.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://viz.greynoise.io/table"><b>GreyNoise</b></a> - mass scanner (such as Shodan and Censys).<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.zoomeye.org/"><b>ZoomEye</b></a> - search engine for cyberspace that lets the user find specific network components.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://fofa.so/"><b>FOFA</b></a> - is a cyberspace search engine.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.onyphe.io/"><b>onyphe</b></a> - is a search engine for open-source and cyber threat intelligence data collected.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://app.binaryedge.io/"><b>binaryedge</b></a> - it scan the entire internet space and create real-time threat intelligence streams and reports.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://hunter.io/"><b>hunter</b></a> - lets you find email addresses in seconds and connect with the people that matter for your business.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://wigle.net/"><b>wigle</b></a> - is a submission-based catalog of wireless networks. All the networks. Found by Everyone.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://publicwww.com/"><b>PublicWWW</b></a> - find any alphanumeric snippet, signature or keyword in the web pages HTML, JS and CSS code.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://inteltechniques.com/menu.html"><b>IntelTechniques</b></a> - this repository contains hundreds of online search utilities.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://ghostproject.fr/"><b>GhostProject?</b></a> - search by full email address or username. <br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://buckets.grayhatwarfare.com/"><b>Buckets by Grayhatwarfar</b></a> - database with public search for Open Amazon S3 Buckets and their contents.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://vigilante.pw/"><b>Vigilante.pw</b></a> - the breached database directory.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://builtwith.com/"><b>builtwith</b></a> - find out what websites are built with.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.mmnt.net/"><b>Mamont's open FTP Index</b></a> - if a target has an open FTP site with accessible content it will be listed here.<br>
</p>

##### :black_small_square: Passwords

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://gotcha.pw/"><b>Gotcha?</b></a> - list of 1.4 billion accounts circulates around the Internet.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://haveibeenpwned.com/"><b>have i been pwned?</b></a> - check if you have an account that has been compromised in a data breach.<br>
</p>

##### :black_small_square: CVE/Exploits databases

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://cve.mitre.org/"><b>CVE Mitre</b></a> - list of publicly known cybersecurity vulnerabilities.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.cvedetails.com/"><b>CVE Details</b></a> - CVE security vulnerability advanced database.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.exploit-db.com/"><b>Exploit DB</b></a> - CVE compliant archive of public exploits and corresponding vulnerable software.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://0day.today/"><b>0day.today</b></a> - exploits market provides you the possibility to buy zero-day exploits and also to sell 0day exploits.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://sploitus.com/"><b>sploitus</b></a> - the exploit and tools database.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://cxsecurity.com/exploit/"><b>cxsecurity</b></a> - free vulnerability database.<br>
</p>

#### Manuals/Howtos/Tutorials

##### :black_small_square: Bash

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/dylanaraps/pure-bash-bible"><b>pure-bash-bible</b></a> - a collection of pure bash alternatives to external processes.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://wiki.bash-hackers.org/start"><b>The Bash Hackers Wiki</b></a> - hold documentation of any kind about GNU Bash.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/contents.html"><b>Shell & Utilities</b></a> - describes the commands and utilities offered to application programs by POSIX-conformant systems.<br>
</p>

##### :black_small_square: Python

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://awesome-python.com/"><b>Awesome Python</b></a> - A curated list of awesome Python frameworks, libraries, software and resources.<br>
</p>

##### :black_small_square: Sed & Awk & Other

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://posts.specterops.io/fawk-yeah-advanced-sed-and-awk-usage-parsing-for-pentesters-3-e5727e11a8ad?gi=c8f9506b26b6"><b>F’Awk Yeah!</b></a> - advanced sed and awk usage (Parsing for Pentesters 3).<br>
</p>

##### :black_small_square: \*nix & Network

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.cyberciti.biz/"><b>nixCraft</b></a> - linux and unix tutorials for new and seasoned sysadmin.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.tecmint.com/"><b>TecMint</b></a> - the ideal Linux blog for Sysadmins & Geeks.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.omnisecu.com/"><b>Omnisecu</b></a> - Free Networking, System Administration and Security Tutorials.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://cb.vu/unixtoolbox.xhtml"><b>Unix Toolbox</b></a> - collection of Unix/Linux/BSD commands and tasks which are useful for IT work or for advanced users.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://linuxguideandhints.com/"><b>Linux Guide and Hints</b></a> - tutorials on system administration in Fedora® and CentOS®, including OpenLDAP and FreeIPA.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/bagder/http2-explained"><b>http2-explained</b></a> - a detailed document explaining and documenting HTTP/2.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/bagder/http3-explained"><b>http3-explained</b></a> - a document describing the HTTP/3 and QUIC protocols.<br>
</p>

##### :black_small_square: System hardening

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://highon.coffee/blog/security-harden-centos-7/"><b>Security Harden CentOS 7</b></a> - this walks you through the steps required to security harden CentOS.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://highon.coffee/blog/security-harden-centos-7/"><b>CentOS 7 Server Hardening Guide</b></a> - great guide for hardening CentOS; familiar with OpenSCAP.<br>
</p>

##### :black_small_square: Security & Privacy

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.owasp.org/index.php/Main_Page"><b>OWASP</b></a> - worldwide not-for-profit charitable organization focused on improving the security of software.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.owasp.org/index.php/Category:OWASP_Application_Security_Verification_Standard_Project"><b>OWASP ASVS 3.0.1</b></a> - OWASP Application Security Verification Standard Project.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/Santandersecurityresearch/asvs"><b>OWASP ASVS 3.0.1 Web App</b></a> - simple web app that helps developers understand the ASVS requirements.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.hackingarticles.in/"><b>Hacking Articles</b></a> - LRaj Chandel's Security & Hacking Blog.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/toniblyx/my-arsenal-of-aws-security-tools"><b>AWS security tools</b></a> - make your AWS cloud environment more secure.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://inventory.rawsec.ml/index.html"><b>Rawsec's CyberSecurity Inventory</b></a> - an inventory of tools and resources about CyberSecurity.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://appsecwiki.com/#/"><b>Application Security Wiki</b></a> - is an initiative to provide all application security related resources at one place.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://tls.ulfheim.net/"><b>The Illustrated TLS Connection</b></a> - every byte of a TLS connection explained and reproduced.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://appsecco.com/books/subdomain-enumeration/"><b>The Art of Subdomain Enumeration</b></a> - a reference for subdomain enumeration techniques.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://lifehacker.com/the-comprehensive-guide-to-quitting-google-1830001964"><b>Quitting Google</b></a> - the comprehensive guide to quitting Google.<br>
</p>

##### :black_small_square: Web Apps

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://infosec.mozilla.org/guidelines/web_security.html"><b>Mozilla Web Security</b></a> - help operational teams with creating secure web applications.<br>
</p>

##### :black_small_square: Other

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://bitvijays.github.io/LFC-VulnerableMachines.html"><b>CTF Series : Vulnerable Machines</b></a> - the steps below could be followed to find vulnerabilities and exploits.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://hshrzd.wordpress.com/how-to-start/"><b>How to start RE/malware analysis?</b></a> - collection of some hints and useful links for the beginners.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://lzone.de/cheat-sheet/"><b>LZone Cheat Sheets</b></a> - all cheat sheets.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://cheat.readthedocs.io/en/latest/"><b>Dan’s Cheat Sheets’s</b></a> - massive cheat sheets documentation.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.kegel.com/c10k.html"><b>The C10K problem</b></a> - it's time for web servers to handle ten thousand clients simultaneously, don't you think?<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://bankgradesecurity.com/"><b>Bank Grade Security</b></a> - when companies say they have "Bank Grade Security" they imply that it is a good thing.<b>*</b><br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://nickcraver.com/blog/2017/05/22/https-on-stack-overflow/"><b>HTTPS on Stack Overflow</b></a> - this is the story of a long journey regarding the implementation of SSL.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://drawings.jvns.ca/"><b>Julia's Drawings</b></a> - some drawings about programming and unix world, zines about systems & debugging tools.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://media.defcon.org/DEF%20CON%2026/"><b>DEF CON Media Server</b></a> - great stuff from DEFCON 26.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://labs.ripe.net/Members/cteusche/bgp-meets-cat"><b>BGP Meets Cat</b></a> - after 3072 hours of manipulating BGP, Job Snijders has succeeded in drawing a Nyancat.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://robertheaton.com/2018/11/28/https-in-the-real-world/"><b>HTTPS in the real world</b></a> - great tutorial explain how HTTPS works in the real world.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://about.gitlab.com/2018/11/14/how-we-spent-two-weeks-hunting-an-nfs-bug/"><b>Gitlab and NFS bug</b></a> - how we spent two weeks hunting an NFS bug in the Linux kernel.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://medium.com/@_bl4de/hidden-directories-and-files-as-a-source-of-sensitive-information-about-web-application-84e5c534e5ad"><b>Hidden directories</b></a> - hidden directories and files as a source of sensitive information about web application.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.catb.org/esr/faqs/hacker-howto.html"><b>How To Become A Hacker</b></a> - if you want to be a hacker, keep reading.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://ithare.com/infographics-operation-costs-in-cpu-clock-cycles/"><b>Operation Costs in CPU</b></a> - an infographics which should help to estimate costs of certain operations in CPU clocks.<br>
</p>

#### Blogs

##### :black_small_square: Geeky Blogs/Persons

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.brendangregg.com/"><b>Brendan Gregg's Blog</b></a> - Brendan Gregg is an industry expert in computing performance and cloud computing.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://gynvael.coldwind.pl/"><b>Gynvael "GynDream" Coldwind</b></a> - Gynvael is a IT security engineer at Google.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://lcamtuf.coredump.cx/"><b>Michał "lcamtuf" Zalewski</b></a> - "white hat" hacker, computer security expert.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://ma.ttias.be/"><b>Mattias Geniar</b></a> - developer, Sysadmin, Blogger, Podcaster and Public Speaker.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://nickcraver.com/"><b>Nick Craver</b></a> - Software Developer and Systems Administrator for Stack Exchange.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://robert.penz.name/"><b>Robert Penz</b></a> - IT security Expert.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://scotthelme.co.uk/"><b>Scott Helme</b></a> - Security Researcher, international speaker and founder of securityheaders.com and report-uri.com.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://twitter.com/binitamshah"><b>Binni Shah</b></a> - Linux Evangelist. Malwares. Kernel Dev. Security Enthusiast.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://security.szurek.pl/"><b>Kacper Szurek</b></a> - Detection Engineer at ESET.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.troyhunt.com/"><b>Troy Hunt</b></a> -  Microsoft Regional Director and Microsoft Most Valuable Professional for Developer Security.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://linux-audit.com/"><b>Linux Audit</b></a> - the Linux security blog about Auditing, Hardening and Compliance by Michael Boelen.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://linuxsecurity.expert/"><b>
Linux Security Expert</b></a> - trainings, howtos, checklists, security tools and more.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.grymoire.com/"><b>The Grymoire</b></a> - collection of useful incantations for wizards, be you computer wizards, magicians, or whatever.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://raymii.org/s/index.html"><b>raymii.org</b></a> - linux/unix sysadmin specializing in building high availability cloud environments.<br>
</p>

##### :black_small_square: A piece of history

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://ftp.arl.army.mil/~mike/howto/"><b>How to Do Things at ARL</b></a> - how to configure modems, scan images, record CD-ROMs, and other useful techniques.<br>
</p>

#### Systems/Services

##### :black_small_square: Systems

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.slackware.com/"><b>Slackware</b></a> - the most "Unix-like" Linux distribution.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.openbsd.org/"><b>OpenBSD</b></a> - multi-platform 4.4BSD-based UNIX-like operating system.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://hardenedbsd.org/"><b>HardenedBSD</b></a> - HardenedBSD aims to implement innovative exploit mitigation and security solutions.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.kali.org/"><b>Kali Linux</b></a> - Linux distribution used for Penetration Testing, Ethical Hacking and network security assessments.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://backbox.org/"><b>Backbox Linux</b></a> - penetration test and security assessment oriented Ubuntu-based Linux distribution.<br>
</p>

##### :black_small_square: HTTP(s) Services

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://varnish-cache.org/"><b>Varnish HTTP Cache</b></a> - HTTP accelerator designed for content-heavy dynamic web sites.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://nginx.org/"><b>Nginx</b></a> - open source web and reverse proxy server that is similar to Apache, but very light weight.<br>
</p>

##### :black_small_square: Secure WebMail Providers

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://countermail.com/"><b>CounterMail</b></a> - is a secure and easy to use online email service, designed to provide maximum security and privacy.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://mail2tor.com/"><b>Mail2Tor</b></a> - is a Tor Hidden Service that allows anyone to send and receive emails anonymously.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://protonmail.com/"><b>Protonmail</b></a> - is the world's largest secure email service, developed by CERN and MIT scientists.<br>
</p>

##### :black_small_square: Crypto

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://keybase.io/"><b>Keybase</b></a> - it's open source and powered by public-key cryptography.<br>
</p>

##### :black_small_square: PGP Keyservers

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://keyserver.ubuntu.com/"><b>SKS OpenPGP Key server</b></a> - includes a highly-efficient reconciliation algorithm for keeping the keyservers synchronized.<br>
</p>

##### :black_small_square: Security/hardening

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://emeraldonion.org/"><b>Emerald Onion</b></a> - seattle-based encrypted-transit internet service provider.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.unbound.net/"><b>Unbound</b></a> - validating, recursive, and caching DNS resolver (with TLS).<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.knot-resolver.cz/"><b>Knot Resolver</b></a> - caching full resolver implementation, including both a resolver library and a daemon.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://vulnreport.io/"><b>Vulnreport</b></a> - open-source pentesting management and automation platform by Salesforce Product Security.<br>
</p>

#### Networks

##### :black_small_square: Tools

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.capanalysis.net/ca/"><b>CapAnalysis</b></a> - web visual tool to analyze large amounts of captured network traffic (PCAP analyzer).<br>
</p>

##### :black_small_square: Labs

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://labs.networkreliability.engineering/"><b>NRE Labs</b></a> - learn automation by doing it. Right now, right here, in your browser.<br>
</p>

#### Awesome Lists

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/kahun/awesome-sysadmin"><b>Awesome Sysadmin</b></a> - amazingly awesome open source sysadmin resources.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/alebcay/awesome-shell"><b>Awesome Shell</b></a> - awesome command-line frameworks, toolkits, guides and gizmos.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/k4m4/movies-for-hackers"><b>Movies for Hackers</b></a> - list of movies every hacker & cyberpunk must watch.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/caesar0301/awesome-pcaptools"><b>Awesome Pcaptools</b></a> - collection of tools developed by other researchers to process network traces.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/leandromoreira/linux-network-performance-parameters"><b>Linux Network Performance</b></a> - learn where some of the network sysctl variables fit into the Linux/Kernel network flow.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/binhnguyennus/awesome-scalability"><b>Awesome Scalability</b></a> - best practices in building High Scalability, High Availability, High Stability and more.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/dhamaniasad/awesome-postgres"><b>Awesome Postgres</b></a> - list of awesome PostgreSQL software, libraries, tools and resources.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/learnbyexample/Command-line-text-processing"><b>Command-line-text-processing</b></a> - from finding text to search and replace, from sorting to beautifying text and more.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/Hack-with-Github/Free-Security-eBooks"><b>Free Security eBooks</b></a> - list of a Free Security and Hacking eBooks.<br>
</p>

#### Hacking/Penetration Testing

##### :black_small_square: Pentesters arsenal tools

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.syhunt.com/sandcat/"><b>Sandcat Browser</b></a> - a penetration-oriented browser with plenty of advanced functionality already built in.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.metasploit.com/"><b>Metasploit</b></a> - tool and framework for pentesting system, web and many more, contains a lot a ready to use exploit.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://portswigger.net/burp"><b>Burp Suite</b></a> - tool for testing Web application security, intercepting proxy to replay, inject, scan and fuzz HTTP requests.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.owasp.org/index.php/OWASP_Zed_Attack_Proxy_Project"><b>OWASP Zed Attack Proxy</b></a> - intercepting proxy to replay, inject, scan and fuzz HTTP requests.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://w3af.org/"><b>w3af</b></a> - is a Web Application Attack and Audit Framework.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://cirt.net/Nikto2"><b>Nikto2</b></a> - web server scanner which performs comprehensive tests against web servers for multiple items.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://sqlmap.org/"><b>sqlmap</b></a> - tool that automates the process of detecting and exploiting SQL injection flaws.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.faradaysec.com/"><b>Faraday</b></a> - an Integrated Multiuser Pentest Environment.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/zardus/ctf-tools"><b>ctf-tools</b></a> - some setup scripts for security research tools.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/bl4de/security-tools"><b>security-tools</b></a> - collection of small security tools created mostly in Python. CTFs, pentests and so on.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/fuzzdb-project/fuzzdb"><b>fuzzdb</b></a> - dictionary of attack patterns and primitives for black-box application fault injection and resource discovery.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/longld/peda"><b>GDB PEDA</b></a> - Python Exploit Development Assistance for GDB.<br>
</p>

##### :black_small_square: Pentests bookmarks collection

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.pentest-standard.org/index.php/Main_Page"><b>PTES</b></a> - the penetration testing execution standard.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.amanhardikar.com/mindmaps/Practice.html"><b>Pentests MindMap</b></a> - amazing mind map with vulnerable apps and systems.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.amanhardikar.com/mindmaps/webapptest.html"><b>WebApps Security Tests MindMap</b></a> - incredible mind map for WebApps security tests.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://brutelogic.com.br/blog/"><b>Brute XSS</b></a> - master the art of Cross Site Scripting.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://jivoi.github.io/2015/07/03/offensive-security-bookmarks/"><b>Offensive Security Bookmarks</b></a> - security bookmarks collection, all that things I need to pass OSCP.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/danielmiessler/SecLists"><b>SecLists</b></a> - collection of multiple types of lists used during security assessments, collected in one place.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/coreb1t/awesome-pentest-cheat-sheets"><b>Awesome Pentest Cheat Sheets</b></a> - collection of the cheat sheets useful for pentesting.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/Hack-with-Github/Awesome-Hacking"><b>Awesome Hacking by HackWithGithub</b></a> - awesome lists for hackers, pentesters and security researchers.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/carpedm20/awesome-hacking"><b>Awesome Hacking by carpedm20</b></a> - a curated list of awesome hacking tutorials, tools and resources.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/vitalysim/Awesome-Hacking-Resources"><b>Awesome Hacking Resources</b></a> - collection of hacking/penetration testing resources to make you better.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/enaqx/awesome-pentest"><b>Awesome Pentest</b></a> - collection of awesome penetration testing resources, tools and other shiny things.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/ksanchezcld/Hacking_Cheat_Sheet"><b>Hacking Cheat Sheet</b></a> - author hacking and pentesting notes.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://brutelogic.com.br/blog/"><b>Pentest Bookmarks</b></a> - there are a LOT of pentesting blogs.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/swisskyrepo/PayloadsAllTheThings"><b>PayloadsAllTheThings</b></a> - a list of useful payloads and bypass for Web Application Security and Pentest/CTF.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://highon.coffee/blog/penetration-testing-tools-cheat-sheet/"><b>Pentesting Tools Cheat Sheet</b></a> - a quick reference high level overview for typical penetration testing engagements.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.netsparker.com/blog/web-security/sql-injection-cheat-sheet/"><b>SQL Injection Cheat Sheet</b></a> - detailed technical information about the many different variants of the SQL Injection.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://kb.entersoft.co.in/"><b>Entersoft Knowledge Base</b></a> - great and detailed reference about vulnerabilities.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://html5sec.org/"><b>HTML5 Security Cheatsheet</b></a> - a collection of HTML5 related XSS attack vectors.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://evuln.com/tools/xss-encoder/"><b>XSS String Encoder</b></a> - for generating XSS code to check your input validation filters against XSS.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://gtfobins.github.io/"><b>GTFOBins</b></a> - list of Unix binaries that can be exploited by an attacker to bypass local security restrictions.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://guif.re/"><b>Guifre Ruiz Notes</b></a> - collection of security, system, network and pentest cheatsheets.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://blog.safebuff.com/2016/07/03/SSRF-Tips/index.html"><b>SSRF Tips</b></a> - a collection of SSRF Tips.<br>
</p>

##### :black_small_square: Bounty programs

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://bountyfactory.io/"><b>Bounty Factory</b></a> - European bug bounty platform based on the legislation and rules in force in European countries.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.openbugbounty.org/"><b>Openbugbounty</b></a> - allows any security researcher reporting a vulnerability on any website.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.hackerone.com/"><b>hackerone</b></a> - global hacker community to surface the most relevant security issues.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.bugcrowd.com/"><b>bugcrowd</b></a> - crowdsourced cybersecurity for the enterprise.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://crowdshield.com/"><b>Crowdshield</b></a> - crowdsourced Security & Bug Bounty Management.<br>
</p>

##### :black_small_square: Web Training Apps (local installation)

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://metasploit.help.rapid7.com/docs/metasploitable-2"><b>OWASP-VWAD</b></a> - comprehensive and well maintained registry of all known vulnerable web applications.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://metasploit.help.rapid7.com/docs/metasploitable-2"><b>Metasploitable 2</b></a> - vulnerable web application amongst security researchers.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://www.dvwa.co.uk/"><b>DVWA</b></a> - PHP/MySQL web application that is damn vulnerable.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://sourceforge.net/projects/mutillidae/"><b>OWASP Mutillidae II</b></a> - free, open source, deliberately vulnerable web-application.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.owasp.org/index.php/OWASP_Juice_Shop_Project"><b>OWASP Juice Shop Project</b></a> - the most bug-free vulnerable application in existence.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.owasp.org/index.php/Category:OWASP_WebGoat_Project"><b>OWASP WebGoat Project</b></a> - insecure web application maintained by OWASP designed to teach web app security.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/opendns/Security_Ninjas_AppSec_Training"><b>Security Ninjas</b></a> - open source application security training program.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/rapid7/hackazon"><b>hackazon</b></a> - a modern vulnerable web app.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/appsecco/dvna"><b>dvna</b></a> - damn vulnerable NodeJS application.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://google-gruyere.appspot.com/"><b>Google Gruyere</b></a> - web application exploits and defenses.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://github.com/amolnaik4/bodhi"><b>Bodhi</b></a> - is a playground focused on learning the exploitation of client-side web vulnerabilities.<br>
</p>

##### :black_small_square: Labs (ethical hacking platforms/trainings)

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.offensive-security.com/"><b>Offensive Security</b></a> - true performance-based penetration testing training for over a decade.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.hackthebox.eu/"><b>Hack The Box</b></a> - online platform allowing you to test your penetration testing skills.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.hacking-lab.com/index.html"><b>Hacking-Lab</b></a> - online ethical hacking, computer network and security challenge platform.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://pwnable.kr/index.php"><b>pwnable.kr</b></a> - non-commercial wargame site which provides various pwn challenges regarding system exploitation.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://pwnable.tw/"><b>Pwnable.tw</b></a> - is a wargame site for hackers to test and expand their binary exploiting skills.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://silesiasecuritylab.com/"><b>Silesia Security Lab</b></a> - high quality security testing services.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://practicalpentestlabs.com/"><b>Practical Pentest Labs</b></a> - pentest lab, take your Hacking skills to the next level.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.root-me.org/?lang=en"><b>Root Me</b></a> - the fast, easy, and affordable way to train your hacking skills.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://rozwal.to/login"><b>rozwal.to</b></a> - a great platform to train your pentesting skills.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://tryhackme.com/"><b>TryHackMe</b></a> - learning Cyber Security made easy.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="http://overthewire.org/wargames/"><b>OverTheWire</b></a> - can help you to learn and practice security concepts in the form of fun-filled games.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://labs.wizard-security.net/"><b>Wizard Labs</b></a> - is an online Penetration Testing Lab.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://pentesterlab.com/"><b>PentesterLab</b></a> - provides vulnerable systems that can be used to test and understand vulnerabilities.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://ringzer0ctf.com/"><b>RingZer0</b></a> - tons of challenges designed to test and improve your hacking skills.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.ubeeri.com/preconfig-labs"><b>Ubeeri</b></a> - preconfigured lab environments.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://lab.pentestit.ru/"><b>Pentestit</b></a> - emulate an IT infrastructure of real companies for a legal pen testing and improving penetration testing skills.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://microcorruption.com/"><b>Microcorruption</b></a> - reversal challenges done in the web interface.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://crackmes.one/"><b>Crackmes</b></a> - download crackmes to help improve your reverse engineering skills.<br>
</p>

#### Your daily knowledge and news

##### :black_small_square: RSS Readers

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://feedly.com/"><b>Feedly</b></a> - organize, read and share what matters to you.<br>
</p>

##### :black_small_square: Security

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://securitynewsletter.co/"><b>Security Newsletter</b></a> - security news as a weekly digest (email notifications).<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://security.googleblog.com/"><b>Google Online Security Blog</b></a> - the latest news and insights from Google on security and safety on the Internet.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://blog.qualys.com/"><b>Qualys Blog</b></a> - expert network security guidance and news.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.darkreading.com/"><b>DARKReading</b></a> - connecting the Information Security Community.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://twitter.com/disclosedh1"><b>publiclyDisclosed</b></a> - public disclosure watcher who keeps you up to date about the recently disclosed bugs.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://packetstormsecurity.com/"><b>Packet Storm</b></a> - information security services, news, files, tools, exploits, aAdvisories and whitepapers.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://sekurak.pl/"><b>Sekurak</b></a> - about security, penetration tests, vulnerabilities and many others (PL/EN).<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://nfsec.pl/"><b>nf.sec</b></a> - basic aspects and mechanisms of Linux operating system security (PL).<br>
</p>

#### Other Cheat Sheets

###### DNS Servers list (privacy)

| <b><u>IP</u></b> | <b><u>URL</u></b> |
| :---         | :---         |
| **`84.200.69.80`** | [dns.watch](https://dns.watch/) |
| **`94.247.43.254`** | [opennic.org](https://www.opennic.org/) |
| **`64.6.64.6`** | [verisign.com](https://www.verisign.com/en_US/security-services/public-dns/index.xhtml) |
| **`89.233.43.71`** | [censurfridns.dk](https://blog.uncensoreddns.org/) |
| **`1.1.1.1`** | [cloudflare.com](https://www.cloudflare.com/dns/) |
| **`94.130.110.185`** | [dnsprivacy.at](https://dnsprivacy.at/) |

###### Build your own DNS Servers

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://calomel.org/unbound_dns.html"><b>Unbound DNS Tutorial</b></a> - a validating, recursive, and caching DNS server.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.ctrl.blog/entry/knot-dns-resolver-tutorial"><b>Knot Resolver on Fedora</b></a> - how to get faster and more secure DNS resolution with Knot Resolver on Fedora.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://www.aaflalo.me/2018/10/tutorial-setup-dns-over-https-server/"><b>DNS-over-HTTPS</b></a> - tutorial to setup your own DNS-over-HTTPS (DoH) server.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://zwischenzugs.com/2018/01/26/how-and-why-i-run-my-own-dns-servers/"><b>DNS Servers</b></a> - how (and why) i run my own DNS Servers.<br>
&nbsp;&nbsp;:small_orange_diamond: <a href="org"><b>DNS Privacy Server</b></a> - running your own DoT or DoH server this page provides some ideas.<br>
</p>

###### Build your own Certificate Authority

<p>
&nbsp;&nbsp;:small_orange_diamond: <a href="https://jamielinux.com/docs/openssl-certificate-authority/"><b>OpenSSL Certificate Authority</b></a> - build your own certificate authority (CA) using the OpenSSL command-line tools.<br>
</p>

###### TOP 10 Browser extensions

| <b><u>Extension name</u></b> | <b><u>Description</u></b> |
| :---         | :---         |
| **`IPvFoo`** | Display the server IP address and HTTPS information across all page elements. |
| **`FoxyProxy`** | Simplifies configuring browsers to access proxy-servers. |
| **`HTTPS Everywhere`** | Automatically use HTTPS security on many sites. |
| **`uMatrix`** | Point & click to forbid/allow any class of requests made by your browser. |
| **`uBlock Origin`** | An efficient blocker: easy on memory and CPU footprint. |
| **`Session Buddy`** | Manage browser tabs and bookmarks with ease. |
| **`SuperSorter`** | Sort bookmarks recursively, delete duplicates, merge folders and more. |
| **`Clear Cache`** | Clear your cache and browsing data. |
| **`d3coder`** | Encoding/Decoding plugin for various types of encoding. |
| **`Web Developer`** | Adds a toolbar button with various web developer tools. |

###### TOP 12 Burp extensions

| <b><u>Extension name</u></b> | <b><u>Description</u></b> |
| :---         | :---         |
| **`Autorize`** | Automatically detects authorization enforcement. |
| **`Reflection`** | An efficient blocker: easy on memory and CPU footprint. |
| **`Logger++`** | Logs requests and responses for all Burp tools in a sortable table. |
| **`Bypass WAF`** | Adds headers useful for bypassing some WAF devices. |
| **`JSON Beautifier`** | Beautifies JSON content in the HTTP message viewer. |
| **`JSON Web Tokens`** | Enables Burp to decode and manipulate JSON web tokens. |
| **`CSP Auditor`** | Displays CSP headers for responses, and passively reports CSP weaknesses. |
| **`CSP-Bypass`** | Passively scans for CSP headers that contain known bypasses.. |
| **`Hackvertor`** | Converts data using a tag-based configuration to apply various encoding. |
| **`Active Scan++`** | Extends Burp's active and passive scanning capabilities. |
| **`HTML5 Auditor`** | Scans for usage of risky HTML5 features. |
| **`Software Vulnerability Scanner`** | Software vulnerability scanner based on Vulners.com audit API. |

#### One-liners

##### Table of Contents

- **[System](#system)**
  * [terminal](#tool-terminal)
  * [mount](#tool-mount)
  * [fuser](#tool-fuser)
  * [ps](#tool-ps)
  * [top](#tool-top)
  * [strace](#tool-strace)
  * [kill](#tool-kill)
  * [find](#tool-find)
  * [diff](#tool-diff)
  * [tail](#tool-tail)
  * [cpulimit](#tool-cpulimit)
  * [pwdx](#tool-pwdx)
  * [tr](#tool-tr)
  * [chmod](#tool-chmod)
  * [who](#tool-who)
  * [last](#tool-last)
  * [screen](#tool-screen)
  * [du](#tool-du)
  * [inotifywait](#tool-inotifywait)
  * [openssl](#tool-openssl)
  * [gnutls-cli](#tool-gnutls-cli)
  * [secure-delete](#tool-secure-delete)
  * [dd](#tool-dd)
- **[HTTP/HTTPS](#http-https)**
  * [curl](#tool-curl)
  * [httpie](#tool-httpie)
- **[Network](#network)**
  * [ssh](#tool-ssh)
  * [linux-dev](#tool-linux-dev)
  * [tcpdump](#tool-tcpdump)
  * [tcpick](#tool-tcpick)
  * [ngrep](#tool-ngrep)
  * [hping3](#tool-hping3)
  * [netcat](#tool-netcat)
  * [socat](#tool-socat)
  * [lsof](#tool-lsof)
  * [netstat](#tool-netstat)
  * [rsync](#tool-rsync)
  * [host](#tool-host)
  * [dig](#tool-dig)
  * [network-other](#tool-network-other)
- **[Programming](#programming)**
  * [awk](#tool-awk)
  * [sed](#tool-sed)
  * [grep](#tool-grep)

<a name="system"><b>System</b></a>

##### Tool: [terminal](https://en.wikipedia.org/wiki/Linux_console)

###### Reload shell without exit

```bash
exec $SHELL -l
```

###### Close shell keeping all subprocess running

```bash
disown -a && exit
```

###### Exit without saving shell history

```bash
kill -9 $$
unset HISTFILE && exit
```

###### Perform a branching conditional

```bash
true && echo success
false || echo failed
```

###### Pipe stdout and stderr to separate commands

```bash
some_command > >(/bin/cmd_for_stdout) 2> >(/bin/cmd_for_stderr)
```

###### Redirect stdout and stderr each to separate files and print both to the screen

```bash
(some_command 2>&1 1>&3 | tee errorlog ) 3>&1 1>&2 | tee stdoutlog
```

###### List of commands you use most often

```bash
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 20
```

###### Quickly backup a file

```bash
cp filename{,.orig}
```

###### Empty a file (truncate to 0 size)

```bash
>filename
```

###### Delete all files in a folder that don't match a certain file extension

```bash
rm !(*.foo|*.bar|*.baz)
```

###### Pass multi-line string to a file

```bash
# cat  >filename ... - overwrite file
# cat >>filename ... - append to file
cat > filename << __EOF__
data data data
__EOF__
```

###### Edit a file on a remote host using vim

```bash
vim scp://user@host//etc/fstab
```

###### Create a directory and change into it at the same time

```bash
mkd () { mkdir -p "$@" && cd "$@"; }
```

###### Convert uppercase files to lowercase files

```bash
rename 'y/A-Z/a-z/' *
```

###### Print a row of characters across the terminal

```bash
printf "%`tput cols`s" | tr ' ' '#'
```

###### Show shell history without line numbers

```bash
history | cut -c 8-
fc -l -n 1 | sed 's/^\s*//'
```

###### Run command(s) after exit session

```bash
cat > /etc/profile << __EOF__
_after_logout() {

  username=$(whoami)

  for _pid in $(ps afx | grep sshd | grep "$username" | awk '{print $1}') ; do

    kill -9 $_pid

  done

}
trap _after_logout EXIT
__EOF__
```

###### Generate a sequence of numbers

```bash
for ((i=1; i<=10; i+=2)) ; do echo $i ; done
# alternative: seq 1 2 10

for ((i=5; i<=10; ++i)) ; do printf '%02d\n' $i ; done
# alternative: seq -w 5 10
```

___

##### Tool: [mount](https://en.wikipedia.org/wiki/Mount_(Unix))

###### Mount a temporary ram partition

```bash
mount -t tmpfs tmpfs /mnt -o size=64M
```

  * `-t` - filesystem type
  * `-o` - mount options

###### Remount a filesystem as read/write

```bash
mount -o remount,rw /
```

___

##### Tool: [fuser](https://en.wikipedia.org/wiki/Fuser_(Unix))

###### Kills a process that is locking a file

```bash
fuser -k filename
```

###### Show what PID is listening on specific port

```bash
fuser -v 53/udp
```

___

##### Tool: [ps](https://en.wikipedia.org/wiki/Ps_(Unix))

###### Show a 4-way scrollable process tree with full details

```bash
ps awwfux | less -S
```

###### Processes per user counter

```bash
ps hax -o user | sort | uniq -c | sort -r
```

___

##### Tool: [find](https://en.wikipedia.org/wiki/Find_(Unix))

###### Find files that have been modified on your system in the past 60 minutes

```bash
find / -mmin 60 -type f
```

###### Find all files larger than 20M

```bash
find / -type f -size +20M
```

###### Find duplicate files (based on MD5 hash)

```bash
find -type f -exec md5sum '{}' ';' | sort | uniq --all-repeated=separate -w 33
```

###### Change permission only for files

```bash
cd /var/www/site && find . -type f -exec chmod 766 {} \;
cd /var/www/site && find . -type f -exec chmod 664 {} +
```

###### Change permission only for directories

```bash
cd /var/www/site && find . -type d -exec chmod g+x {} \;
cd /var/www/site && find . -type d -exec chmod g+rwx {} +
```

###### Find files and directories for specific user

```bash
find . -user <username> -print
```

###### Find files and directories for all without specific user

```bash
find . \!-user <username> -print
```

###### Delete older files than 60 days

```bash
find . -type f -mtime +60 -delete
```

###### Recursively remove all empty sub-directories from a directory

```bash
find . -depth  -type d  -empty -exec rmdir {} \;
```

###### How to find all hard links to a file

```bash
find </path/to/dir> -xdev -samefile filename
```

###### Recursively find the latest modified files

```bash
find . -type f -exec stat --format '%Y :%y %n' "{}" \; | sort -nr | cut -d: -f2- | head
```

___

##### Tool: [top](https://en.wikipedia.org/wiki/Top_(software))

###### Use top to monitor only all processes with the specific string

```bash
top -p $(pgrep -d , <str>)
```

  * `<str>` - process containing str (eg. nginx, worker)

___

##### Tool: [strace](https://en.wikipedia.org/wiki/Strace)

###### Track child process

```bash
strace -f -p $(pidof glusterfsd)
```

###### Track process after 30 seconds

```bash
timeout 30 strace $(< /var/run/zabbix/zabbix_agentd.pid)
```

###### Track child process and redirect output to a file

```bash
ps auxw | grep 'sbin/[a]pache' | awk '{print " -p " $2}' | xargs strace -o /tmp/strace-apache-proc.out
```

###### Track the open request of a network port

```bash
strace -f -e trace=bind nc -l 80
```

###### Track the open request of a network port (show TCP/UDP)

```bash
strace -f -e trace=network nc -lu 80
```

___

##### Tool: [kill](https://en.wikipedia.org/wiki/Kill_(command))

###### Kill a process running on port

```bash
kill -9 $(lsof -i :<port> | awk '{l=$2} END {print l}')
```

___

##### Tool: [diff](https://en.wikipedia.org/wiki/Diff)

###### Compare two directory trees

```bash
diff <(cd directory1 && find | sort) <(cd directory2 && find | sort)
```

___

##### Tool: [tail](https://en.wikipedia.org/wiki/Tail_(Unix))

###### Annotate tail -f with timestamps

```bash
tail -f file | while read ; do echo "$(date +%T.%N) $REPLY" ; done
```

###### Analyse an Apache access log for the most common IP addresses

```bash
tail -10000 access_log | awk '{print $1}' | sort | uniq -c | sort -n | tail
```

###### Analyse web server log and show only 5xx http codes

```bash
tail -n 100 -f /path/to/logfile | grep "HTTP/[1-2].[0-1]\" [5]"
```

___

##### Tool: [tar](https://en.wikipedia.org/wiki/Tar_(computing))

###### System backup with exclude specific directories

```bash
cd /
tar -czvpf /mnt/system$(date +%d%m%Y%s).tgz --directory=/ \
--exclude=proc/* --exclude=sys/* --exclude=dev/* --exclude=mnt/* .
```

###### System backup with exclude specific directories (pigz)

```bash
cd /
tar cvpf /backup/snapshot-$(date +%d%m%Y%s).tgz --directory=/ \
--exclude=proc/* --exclude=sys/* --exclude=dev/* \
--exclude=mnt/* --exclude=tmp/* --use-compress-program=pigz .
```

___

##### Tool: [dump](https://en.wikipedia.org/wiki/Dump_(program))

###### System backup to file

```bash
dump -y -u -f /backup/system$(date +%d%m%Y%s).lzo /
```

###### Restore system from lzo file

```bash
cd /
restore -rf /backup/system$(date +%d%m%Y%s).lzo
```

___

##### Tool: [cpulimit](http://cpulimit.sourceforge.net/)

###### Limit the cpu usage of a process

```bash
cpulimit -p pid -l 50
```

___

##### Tool: [pwdx](https://www.cyberciti.biz/faq/unix-linux-pwdx-command-examples-usage-syntax/)

###### Show current working directory of a process

```bash
pwdx <pid>
```

___

##### Tool: [taskset](https://www.cyberciti.biz/faq/taskset-cpu-affinity-command/)

###### Start a command on only one CPU core

```bash
taskset -c 0 <command>
```

___

##### Tool: [tr](https://en.wikipedia.org/wiki/Tr_(Unix))

###### Show directories in the PATH, one per line

```bash
tr : '\n' <<<$PATH
```

___

##### Tool: [chmod](https://en.wikipedia.org/wiki/Chmod)

###### Remove executable bit from all files in the current directory

```bash
chmod -R -x+X *
```

###### Restore permission for /bin/chmod

```bash
# 1:
cp /bin/ls chmod.01
cp /bin/chmod chmod.01
./chmod.01 700 file

# 2:
/bin/busybox chmod 0700 /bin/chmod

# 3:
setfacl --set u::rwx,g::---,o::--- /bin/chmod
```

___

##### Tool: [who](https://en.wikipedia.org/wiki/Who_(Unix))

###### Find last reboot time

```bash
who -b
```

###### Detect a user sudo-su'd into the current shell

```bash
[[ $(who -m | awk '{ print $1 }') == $(whoami) ]] || echo "You are su-ed to $(whoami)"
```

___

##### Tool: [last](https://www.howtoforge.com/linux-last-command/)

###### Was the last reboot a panic?

```bash
(last -x -f $(ls -1t /var/log/wtmp* | head -2 | tail -1); last -x -f /var/log/wtmp) | grep -A1 reboot | head -2 | grep -q shutdown && echo "Expected reboot" || echo "Panic reboot"
```

___

##### Tool: [screen](https://en.wikipedia.org/wiki/GNU_Screen)

###### Start screen in detached mode

```bash
screen -d -m [<command>]
```

___

##### Tool: [du](https://en.wikipedia.org/wiki/GNU_Screen)

###### Show 20 biggest directories with 'K M G'

```bash
du | \
sort -r -n | \
awk '{split("K M G",v); s=1; while($1>1024){$1/=1024; s++} print int($1)" "v[s]"\t"$2}' | \
head -n 20
```

___

##### Tool: [inotifywait](https://en.wikipedia.org/wiki/GNU_Screen)

###### Init tool everytime a file in a directory is modified

```bash
while true ; do inotifywait -r -e MODIFY dir/ && ls dir/ ; done;
```

___

##### Tool: [openssl](https://www.openssl.org/)

###### Testing connection to remote host

```bash
echo | openssl s_client -connect google.com:443 -showcerts
```

###### Testing connection to remote host (with SNI support)

```bash
echo | openssl s_client -showcerts -servername google.com -connect google.com:443
```

###### Testing connection to remote host with specific ssl version

```bash
openssl s_client -tls1_2 -connect google.com:443
```

###### Testing connection to remote host with specific ssl cipher

```bash
openssl s_client -cipher 'AES128-SHA' -connect google.com:443
```

###### Generate private key

```bash
# _len: 2048, 4096
( _fd="private.key" ; _len="4096" ; \
openssl genrsa -out ${_fd} ${_len} )
```

###### Generate private key with password

```bash
# _ciph: des3, aes128, aes256
# _len: 2048, 4096
( _ciph="aes128" ; _fd="private.key" ; _len="4096" ; \
openssl genrsa -${_ciph} -out ${_fd} ${_len} )
```

###### Remove password from private key

```bash
( _fd="private.key" ; _fd_unp="private_unp.key" ; \
openssl rsa -in ${_fd} -out ${_fd_unp} )
```

###### Get public key from private key

```bash
( _fd="private.key" ; _fd_pub="public.key" ; \
openssl rsa -pubout -in ${_fd} -out ${_fd_pub} )
```

###### Generate private key + csr

```bash
( _fd="private.key" ; _fd_csr="request.csr" ; _len="4096" ; \
openssl req -out ${_fd_csr} -new -newkey rsa:${_len} -nodes -keyout ${_fd} )
```

###### Generate csr

```bash
( _fd="private.key" ; _fd_csr="request.csr" ; \
openssl req -out ${_fd_csr} -new -key ${_fd} )
```

###### Generate csr (metadata from exist certificate)

```bash
( _fd="private.key" ; _fd_csr="request.csr" ; _fd_crt="cert.crt" ; \
openssl x509 -x509toreq -in ${_fd_crt} -out ${_fd_csr} -signkey ${_fd} )
```

###### Generate csr with -config param

```bash
( _fd="private.key" ; _fd_csr="request.csr" ; \
openssl req -new -sha256 -key ${_fd} -out ${_fd_csr} \
-config <(
cat <<-EOF
[req]
default_bits = 2048
prompt = no
default_md = sha256
req_extensions = req_ext
distinguished_name = dn

[ dn ]
C=<two-letter ISO abbreviation for your country>
ST=<state or province where your organization is legally located>
L=<city where your organization is legally located>
O=<legal name of your organization>
OU=<section of the organization>
CN=<fully qualified domain name>

[ req_ext ]
subjectAltName = @alt_names

[ alt_names ]
DNS.1 = <fully qualified domain name>
DNS.2 = <next domain>
DNS.3 = <next domain>
EOF
))
```

###### Convert DER to PEM

```bash
( _fd_der="cert.crt" ; _fd_pem="cert.pem" ; \
openssl x509 -in ${_fd_der} -inform der -outform pem -out ${_fd_pem} )
```

###### Convert PEM to DER

```bash
( _fd_der="cert.crt" ; _fd_pem="cert.pem" ; \
openssl x509 -in ${_fd_pem} -outform der -out ${_fd_der} )
```

###### Checking whether the private key and the certificate match

```bash
(openssl rsa -noout -modulus -in private.key | openssl md5 ; openssl x509 -noout -modulus -in certificate.crt | openssl md5) | uniq
```

___

##### Tool: [gnutls-cli](https://gnutls.org/manual/html_node/gnutls_002dcli-Invocation.html)

###### Testing connection to remote host (with SNI support)

```bash
gnutls-cli -p 443 google.com
```

###### Testing connection to remote host (without SNI support)

```bash
gnutls-cli --disable-sni -p 443 google.com
```

___

##### Tool: [secure-delete](https://wiki.archlinux.org/index.php/Securely_wipe_disk)

###### Secure delete with shred

```bash
shred -vfuz -n 10 file
shred --verbose --random-source=/dev/urandom -n 1 /dev/sda
```

###### Secure delete with scrub

```bash
scrub -p dod /dev/sda
scrub -p dod -r file
```

###### Secure delete with badblocks

```bash
badblocks -s -w -t random -v /dev/sda
badblocks -c 10240 -s -w -t random -v /dev/sda
```

###### Secure delete with secure-delete

```bash
srm -vz /tmp/file
sfill -vz /local
sdmem -v
swapoff /dev/sda5 && sswap -vz /dev/sda5
```

___

##### Tool: [dd](https://en.wikipedia.org/wiki/Dd_(Unix))

###### Show dd status every so often

```bash
dd <dd_params> status=progress
watch --interval 5 killall -USR1 dd
```

###### Redirect output to a file with dd

```bash
echo "string" | dd of=filename
```

<a name="http-https"><b>HTTP/HTTPS</b></a>

##### Tool: [curl](https://curl.haxx.se)

```bash
curl -Iks https://www.google.com
```

  * `-I` - show response headers only
  * `-k` - insecure connection when using ssl
  * `-s` - silent mode (not display body)

```bash
curl -Iks --location -X GET -A "x-agent" https://www.google.com
```

  * `--location` - follow redirects
  * `-X` - set method
  * `-A` - set user-agent

```bash
curl -Iks --location -X GET -A "x-agent" --proxy http://127.0.0.1:16379 https://www.google.com
```

  * `--proxy [socks5://|http://]` - set proxy server

###### Check DNS and HTTP trace with headers for specific domains

```bash
### Set domains and external dns servers.
_domain_list=(google.com) ; _dns_list=("8.8.8.8" "1.1.1.1")

for _domain in "${_domain_list[@]}" ; do

  printf '=%.0s' {1..48}

  echo

  printf "[\\e[1;32m+\\e[m] resolve: %s\\n" "$_domain"

  for _dns in "${_dns_list[@]}" ; do

    # Resolve domain.
    host "${_domain}" "${_dns}"

    echo

  done

  for _proto in http https ; do

    printf "[\\e[1;32m+\\e[m] trace + headers: %s://%s\\n" "$_proto" "$_domain"

    # Get trace and http headers.
    curl -Iks -A "x-agent" --location "${_proto}://${_domain}"

    echo

  done

done

unset _domain_list _dns_list
```

___

##### Tool: [httpie](https://httpie.org/)

```bash
http -p Hh https://www.google.com
```

  * `-p` - print request and response headers
    * `H` - request headers
    * `B` - request body
    * `h` - response headers
    * `b` - response body

```bash
http -p Hh --follow --max-redirects 5 --verify no https://www.google.com
```

  * `-F, --follow` - follow redirects
  * `--max-redirects N` - maximum for `--follow`
  * `--verify no` - skip SSL verification

```bash
http -p Hh --follow --max-redirects 5 --verify no --proxy http:http://127.0.0.1:16379 https://www.google.com
```

  * `--proxy [http:]` - set proxy server

<a name="network"><b>Network</b></a>

##### Tool: [ssh](https://www.openssh.com/)

###### Compare a remote file with a local file

```bash
ssh user@host cat /path/to/remotefile | diff /path/to/localfile -
```

###### SSH connection through host in the middle

```bash
ssh -t reachable_host ssh unreachable_host
```

###### Run command over ssh on remote host

```bash
cat > cmd.txt << __EOF__
cat /etc/hosts
__EOF__

ssh host -l user $(<cmd.txt)
```

###### Get public key from private key

```bash
ssh-keygen -y -f ~/.ssh/id_rsa
```

###### Get all fingerprints

```bash
ssh-keygen -l -f .ssh/known_hosts
```

###### Ssh authentication with user password

```bash
ssh -o PreferredAuthentications=password -o PubkeyAuthentication=no user@remote_host
```

###### Ssh authentication with publickey

```bash
ssh -o PreferredAuthentications=publickey -o PubkeyAuthentication=yes -i id_rsa user@remote_host
```

###### Simple recording SSH session

```bash
function _ssh_sesslog() {

  _sesdir="<path/to/session/logs>"

  mkdir -p "${_sesdir}" && \
  ssh $@ 2>&1 | tee -a "${_sesdir}/$(date +%Y%m%d).log"

}

# Alias:
alias ssh='_ssh_sesslog'
```

###### Using Keychain for SSH logins

```bash
### Delete all of ssh-agent's keys.
function _scl() {

  /usr/bin/keychain --clear

}

### Add key to keychain.
function _scg() {

  /usr/bin/keychain /path/to/private-key
  source "$HOME/.keychain/$HOSTNAME-sh"

}
```

###### SSH login without processing any login scripts

```bash
ssh -tt user@host bash
```

___

##### Tool: [linux-dev](https://www.tldp.org/LDP/abs/html/devref1.html)

###### Testing remote connection to port

```bash
timeout 1 bash -c "</dev/<proto>/<host>/<port>" >/dev/null 2>&1 ; echo $?
```

  * `<proto` - set protocol (tcp/udp)
  * `<host>` - set remote host
  * `<port>` - set destination port

###### Read and write to TCP or UDP sockets with common bash tools

```bash
exec 5<>/dev/tcp/<host>/<port>; cat <&5 & cat >&5; exec 5>&-
```

___

##### Tool: [tcpdump](http://www.tcpdump.org/)

```bash
tcpdump -ne -i eth0 -Q in host 192.168.252.1 and port 443
```

  * `-n` - don't convert addresses
  * `-e` - print the link-level headers
  * `-i [iface|any]` - set interface
  * `-Q|-D [in|out|inout]` - choose send/receive direction (`-D` - for old tcpdump versions)
  * `host [ip|hostname]` - set host, also `[host not]`
  * `[and|or]` - set logic
  * `port [1-65535]` - set port number, also `[port not]`

```bash
tcpdump -ne -i eth0 -Q in host 192.168.252.1 and port 443 -c 5 -w tcpdump.pcap
```

  * `-c [num]` - capture only num number of packets
  * `-w [filename]` - write packets to file, `-r [filename]` - reading from file

___

##### Tool: [tcpick](http://tcpick.sourceforge.net/)

###### Analyse packets in real-time

```bash
while true ; do tcpick -a -C -r dump.pcap ; sleep 2 ; clear ; done
```

___

##### Tool: [ngrep](http://ngrep.sourceforge.net/usage.html)

```bash
ngrep -d eth0 "www.google.com" port 443
```

  * `-d [iface|any]` - set interface
  * `[domain]` - set hostname
  * `port [1-65535]` - set port number

```bash
ngrep -d eth0 "www.google.com" (host 10.240.20.2) and (port 443)
```

  * `(host [ip|hostname])` - filter by ip or hostname
  * `(port [1-65535])` - filter by port number

```bash
ngrep -d eth0 -qt -O ngrep.pcap "www.google.com" port 443
```

  * `-q` - quiet mode (only payloads)
  * `-t` - added timestamps
  * `-O [filename]` - save output to file, `-I [filename]` - reading from file

```bash
ngrep -d eth0 -qt 'HTTP' 'tcp'
```

  * `HTTP` - show http headers
  * `tcp|udp` - set protocol
  * `[src|dst] host [ip|hostname]` - set direction for specific node

```bash
ngrep -l -q -d eth0 -i "User-Agent: curl*"
```

  * `-l` - stdout line buffered
  * `-i` - case-insensitive search

___

##### Tool: [hping3](http://www.hping.org/)

```bash
hping3 -V -p 80 -s 5050 <scan_type> www.google.com
```

  * `-V|--verbose` - verbose mode
  * `-p|--destport` - set destination port
  * `-s|--baseport` - set source port
  * `<scan_type>` - set scan type
    * `-F|--fin` - set FIN flag, port open if no reply
    * `-S|--syn` - set SYN flag
    * `-P|--push` - set PUSH flag
    * `-A|--ack` - set ACK flag (use when ping is blocked, RST response back if the port is open)
    * `-U|--urg` - set URG flag
    * `-Y|--ymas` - set Y unused flag (0x80 - nullscan), port open if no reply
    * `-M 0 -UPF` - set TCP sequence number and scan type (URG+PUSH+FIN), port open if no reply

```bash
hping3 -V -c 1 -1 -C 8 www.google.com
```

  * `-c [num]` - packet count
  * `-1` - set ICMP mode
  * `-C|--icmptype [icmp-num]` - set icmp type (default icmp-echo = 8)

```bash
hping3 -V -c 1000000 -d 120 -S -w 64 -p 80 --flood --rand-source <remote_host>
```

  * `--flood` - sent packets as fast as possible (don't show replies)
  * `--rand-source` - random source address mode
  * `-d --data` - data size
  * `-w|--win` - winsize (default 64)

___

##### Tool: [netcat](http://netcat.sourceforge.net/)

```bash
nc -kl 5000
```

  * `-l` - listen for an incoming connection
  * `-k` - listening after client has disconnected
  * `>filename.out` - save receive data to file (optional)

```bash
nc 192.168.0.1 5051 < filename.in
```

  * `< filename.in` - send data to remote host

```bash
nc -vz 10.240.30.3 5000
```

  * `-v` - verbose output
  * `-z` - scan for listening daemons

```bash
nc -vzu 10.240.30.3 1-65535
```

  * `-u` - scan only udp ports

###### Transfer data file (archive)

```bash
server> nc -l 5000 | tar xzvfp -
client> tar czvfp - /path/to/dir | nc 10.240.30.3 5000
```

###### Launch remote shell

```bash
server> nc -l 5000 -e /bin/bash
client> nc 10.240.30.3 5000
```

###### Simple file server

```bash
while true ; do nc -l 5000 | tar -xvf - ; done
```

###### Simple minimal HTTP Server

```bash
while true ; do nc -l -p 1500 -c 'echo -e "HTTP/1.1 200 OK\n\n $(date)"' ; done
```

###### Simple HTTP Server

  > Restarts web server after each request - remove `while` condition for only single connection.

```bash
cat > index.html << __EOF__
<!doctype html>
    <head>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
        <title></title>
        <meta name="description" content="">
        <meta name="viewport" content="width=device-width, initial-scale=1">
    </head>
    <body>

    <p>

      Hello! It's a site.

    </p>

    </body>
</html>
__EOF__
```

```bash
server> while : ; do \
(echo -ne "HTTP/1.1 200 OK\r\nContent-Length: $(wc -c <index.html)\r\n\r\n" ; cat index.html;) | \
nc -l -p 5000 \
; done
```

  * `-p` - port number

###### Simple HTTP Proxy (single connection)

```bash
#!/usr/bin/env bash

if [[ $# != 2 ]] ; then
  printf "%s\\n" \
         "usage: ./nc-proxy listen-port bk_host:bk_port"
fi

_listen_port="$1"
_bk_host=$(echo "$2" | cut -d ":" -f1)
_bk_port=$(echo "$2" | cut -d ":" -f2)

printf "  lport: %s\\nbk_host: %s\\nbk_port: %s\\n\\n" \
       "$_listen_port" "$_bk_host" "$_bk_port"

_tmp=$(mktemp -d)
_back="$_tmp/pipe.back"
_sent="$_tmp/pipe.sent"
_recv="$_tmp/pipe.recv"

trap 'rm -rf "$_tmp"' EXIT

mkfifo -m 0600 "$_back" "$_sent" "$_recv"

sed "s/^/=> /" <"$_sent" &
sed "s/^/<=  /" <"$_recv" &

nc -l -p "$_listen_port" <"$_back" | \
tee "$_sent" | \
nc "$_bk_host" "$_bk_port" | \
tee "$_recv" >"$_back"
```

```bash
server> chmod +x nc-proxy && ./nc-proxy 8080 192.168.252.10:8000
  lport: 8080
bk_host: 192.168.252.10
bk_port: 8000

client> http -p h 10.240.30.3:8080
HTTP/1.1 200 OK
Accept-Ranges: bytes
Cache-Control: max-age=31536000
Content-Length: 2748
Content-Type: text/html; charset=utf-8
Date: Sun, 01 Jul 2018 20:12:08 GMT
Last-Modified: Sun, 01 Apr 2018 21:53:37 GMT
```

###### Create a single-use TCP or UDP proxy

```bash
### TCP -> TCP
nc -l -p 2000 -c "nc [ip|hostname] 3000"

### TCP -> UDP
nc -l -p 2000 -c "nc -u [ip|hostname] 3000"

### UDP -> UDP
nc -l -u -p 2000 -c "nc -u [ip|hostname] 3000"

### UDP -> TCP
nc -l -u -p 2000 -c "nc [ip|hostname] 3000"
```

___

##### Tool: [socat](http://www.dest-unreach.org/socat/doc/socat.html/)

###### Testing remote connection to port

```bash
socat - TCP4:10.240.30.3:22
```

  * `-` - standard input (STDIO)
  * `TCP4:<params>` - set tcp4 connection with specific params
    * `[hostname|ip]` - set hostname/ip
    * `[1-65535]` - set port number

###### Redirecting TCP-traffic to a UNIX domain socket under Linux

```bash
socat TCP-LISTEN:1234,bind=127.0.0.1,reuseaddr,fork,su=nobody,range=127.0.0.0/8 UNIX-CLIENT:/tmp/foo
```

  * `TCP-LISTEN:<params>` - set tcp listen with specific params
    * `[1-65535]` - set port number
    * `bind=[hostname|ip]` - set bind hostname/ip
    * `reuseaddr` - allows other sockets to bind to an address
    * `fork` - keeps the parent process attempting to produce more connections
    * `su=nobody` - set user
    * `range=[ip-range]` - ip range
  * `UNIX-CLIENT:<params>` - communicates with the specified peer socket
    * `filename` - define socket

___

##### Tool: [lsof](https://en.wikipedia.org/wiki/Lsof)

###### Show process that use internet connection at the moment

```bash
lsof -P -i -n
```

###### Show process that use specific port number

```bash
lsof -i tcp:443
```

###### Lists all listening ports together with the PID of the associated process

```bash
lsof -Pan -i tcp -i udp
```

###### List all open ports and their owning executables

```bash
lsof -i -P | grep -i "listen"
```

###### Show all open ports

```bash
lsof -Pnl -i
```

###### Show open ports (LISTEN)

```bash
lsof -Pni4 | grep LISTEN | column -t
```

###### List all files opened by a particular command

```bash
lsof -c "process"
```

###### View user activity per directory

```bash
lsof -u username -a +D /etc
```

###### Show 10 Largest Open Files

```bash
lsof / | \
awk '{ if($7 > 1048576) print $7/1048576 "MB" " " $9 " " $1 }' | \
sort -n -u | tail | column -t
```

___

##### Tool: [netstat](https://en.wikipedia.org/wiki/Netstat)

###### Graph # of connections for each hosts

```bash
netstat -an | \
grep ESTABLISHED | \
awk '{print $5}' | \
awk -F: '{print $1}' | \
grep -v -e '^[[:space:]]*$' | \
sort | uniq -c | \
awk '{ printf("%s\t%s\t",$2,$1) ; for (i = 0; i < $1; i++) {printf("*")}; print "" }'
```

###### Monitor open connections for specific port including listen, count and sort it per IP

```bash
watch "netstat -plan | grep :443 | awk {'print \$5'} | cut -d: -f 1 | sort | uniq -c | sort -nk 1"
```

___

##### Tool: [rsync](https://en.wikipedia.org/wiki/Rsync)

###### Rsync remote data as root using sudo

```bash
rsync --rsync-path 'sudo rsync' username@hostname:/path/to/dir/ /local/
```

___

##### Tool: [host](https://en.wikipedia.org/wiki/Host_(Unix))

###### Resolves the domain name (using external dns server)

```bash
host google.com 9.9.9.9
```

###### Checks the domain administrator (SOA record)

```bash
host -t soa google.com 9.9.9.9
```

___

##### Tool: [dig](https://en.wikipedia.org/wiki/Dig_(command))

###### Resolves the domain name (short output)

```bash
dig google.com +short
```

###### Lookup NS record for specific domain

```bash
dig @9.9.9.9 google.com NS
```

###### Query only answer section

```bash
dig google.com +nocomments +noquestion +noauthority +noadditional +nostats
```

###### Query ALL DNS Records

```bash
dig google.com ANY +noall +answer
```

###### DNS Reverse Look-up

```bash
dig -x 172.217.16.14 +short
```

___

##### Tool: [network-other](https://github.com/trimstray/the-book-of-secret-knowledge#tool-network-other)

###### Get all subnets for specific AS (Autonomous system)

```bash
AS="AS32934"
whois -h whois.radb.net -- "-i origin ${AS}" | \
grep "^route:" | \
cut -d ":" -f2 | \
sed -e 's/^[ \t]//' | \
sort -n -t . -k 1,1 -k 2,2 -k 3,3 -k 4,4 | \
cut -d ":" -f2 | \
sed -e 's/^[ \t]/allow /' | \
sed 's/$/;/' | \
sed 's/allow  */subnet -> /g'
```

###### Resolves domain name from dns.google.com with curl and jq

```bash
_dname="google.com" ; curl -s "https://dns.google.com/resolve?name=${_dname}&type=A" | jq .
```

<a name="programming"><b>Programming</b></a>

##### Tool: [awk](http://www.grymoire.com/Unix/Awk.html)

###### Remove duplicate entries in a file without sorting

```bash
awk '!x[$0]++' filename
```

###### Exclude multiple columns using AWK

```bash
awk '{$1=$3=""}1' filename
```

___

##### Tool: [sed](http://www.grymoire.com/Unix/Sed.html)

###### To print a specific line from a file

```bash
sed -n 10p /path/to/file
```

###### Remove a specific line from a file

```bash
sed -i 10d /path/to/file
# alternative (BSD): sed -i'' 10d /path/to/file
```

###### Remove a range of lines from a file

```bash
sed -i <file> -re '<start>,<end>d'
```

___

##### Tool: [grep](http://www.grymoire.com/Unix/Grep.html)

###### Search for a "pattern" inside all files in the current directory

```bash
grep -rn "pattern"
grep -RnisI "pattern" *
fgrep "pattern" * -R
```

###### Remove blank lines from a file and save output to new file

```bash
grep . filename > newfilename
```

###### Except multiple patterns

```bash
grep -vE '(error|critical|warning)' filename
```

###### Show data from file without comments

```bash
grep -v ^[[:space:]]*# filename
```

###### Show data from file without comments and new lines

```bash
egrep -v '#|^$' filename
```