Esysc / my-links

98% OSS
1% free-as-in-beer closed source software
1% in-browser tools
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IT News

A mix of industry and technical, traditional and next generation, dev and ops

Linux News and Articles

Linux-centric news, articles, and discussion

Linux Message Boards and Forums

Resources for troubleshooting and technical questions

Mailing Lists - No link, there's like 4 trillion of them
IRC - Same as above
Arch Linux BBS - Official
Ask Fedora - Official
Ask Ubuntu - StackExchange
CentOS Forums - Official
Fedora Forums
JustLinux Forums
LinuxForums.org
LinuxQuestions.org
linux.stackexchange.com - StackExchange
Linux Mint Forums - Official
Red Hat Support Portal - Subscription required
serverfault.com - StackExchange
superuser.com - StackExchange
SUSE / SLES Support Portal and Knowledge Base - Official
SUSE Forums - Official
UbuntuForums.org - Official
Unix.com Forums

Asset Management

Asset management, inventories, asset discovery, CMDB, and IPAM

Clusto - Inventory tracking and "cluster management" system -- Python
Collins - Infrastructure source of truth, created by Tumblr -- Scala
iTop - IT Service Management (ITSM), asset tracking, and ITIL -- PHP
Fusion Inventory - Multi-lingual, can be paired with GLPI for a killer solution -- perl
Genesis - Hardware discovery, by Tumblr, can report to Collins -- Ruby
GestioIP - IP address management (IPAM), web based, supports discovery -- perl
GLPI - Also provides license management, software auditing, and ticketing -- PHP
HostDB - New tool to help manage data center inventory -- perl
IP Plan - IPAM -- PHP
ITDB (IT ITems DataBase) - Includes purchase order management, floor plans, and ISO20000-like features -- PHP
Netdisco - Web-based network management and discovery tool, written in perl, uses SNMP -- perl
Network UPS Tools (NUT) - Manage power devices from over 100 manufacturers using a single web interface -- C Windows
OCS-NG (OCS Inventory NG - Automated inventory, deployment system, can sync with GLPI -- perl
openDCIM - Data center infrastructure management -- PHP
Open-AudIT - Track and report assets and configurations, supports Windows too -- PHP
phpIPAM - IPAM -- PHP
RackTables - Data center asset management -- PHP
racktables-contribs - RackTables user-contributed plugins -- PHP
Ralph - DCIM and CMDB, supports auto-discovery -- Python pip
rho - Scans for and gathers information about Linux and Unix servers -- Python
Snipe-IT - Uses Bootstrap, web based, supports mobile -- PHP
Tracmor - Web-based inventory and asset tracking system that uses the Qcodo framework -- PHP

AWS Tools

Tools for interacting with the Amazon Web Services ecosystem

Aminator - Create application-specific custom AMIs, by Netflix -- Python
Awesome AWS - Curated list of AWS resources -- collection
aws-shell (formerly Supercharged AWS CLI (SAWS)) - The best CLI for interacting with AWS -- Python pip
awstools - Some handy AWS tools and scripts that use boto3 and troposphere -- Python
Chrome AWS SAML Token Expiry Reminder (CASTER) - Automatically re-logs into AWS via ADFS before credentials expire -- Chrome
cloud-ssh - SSH wrapper that supports hostname tab-completion based on AWS name, tag, or security group -- Golang
CloudBerry Explorer - Windows client for accessing AWS S3 buckets -- closed source Windows
CloudCraft - Create professional AWS architecture diagrams -- in-browser
credstash - Secret management using AWS KMS -- Python pip
Developer Tools - 3rd party tools for AWS - not screened or supported by Amazon -- various lang
DREBS (Disaster Recovery for Elastic Block Store) - Tool for taking periodic snapshots of EBS volumes -- Ruby gem
eb_deploy - Elastic Beanstalk blue-green deployment automation -- Ruby gem
ec2dns - CLI tools to display public host names of instances and SSH into them via their tag -- PHP
ElasticWolf - Client-side GUI for managing AWS -- closed source Windows Firefox OS X
ELB Consul - Docker container that allows you to (de)register EC2 instances belonging to a specific Consul service with an ELB -- Python
haproxy-autoscale - Wrapper for haproxy that handles auto-scaling EC2 instances -- Python
Ice - AWS usage tool, by Netflix -- Grails
ION Roller - Immutable deployment framework for web services -- Scala
jungle - awscli wrapper to make commands simpler and more UNIX-like -- Python pip
kappa - CLI tool that makes it easier to deploy, update, and test Lambda functions -- Python
s3cmd - Backup to AWS via the command line -- Python
Serverless (formerly JAWS) - Javascript + AWS stack, the entire backend is Lambda functions, server-free -- JavaScript
Sneaker - Store secrets on S3 using Amazon KMS -- Golang
ssh2ec2 - SSH into EC2 instances by tag name and/or other metadata filters -- Python pip
StarCluster - Toolkit for using AWS for high performance computing (HPC) -- Python
Stout - Easy way to reliably upload a static website to S3, capable of configuring CloudFront and Route 53 -- Golang
Tools for Amazon Web Services - Amazon's portal for their official tools -- various lang
troposphere - Python library to create CloudFormation descriptions -- Python pip

Backups

Traditional backup software - see also Cloud File Sync and Sharing

Amanda - The classic -- C perl
Attimatic - Wrapper for attic to make it easier and more reliable -- Python
Attic - Written in Python, supports dedupe -- Python
Backupninja - Centralize way to configure and schedule many different backup utilities -- shell
BURP (BackUp and Restore Program) - Reduces network traffic and the amount of space required by using librsync -- C
BackupPC - Dedupe and a web GUI for restores -- perl
Backup - Gem for backup and restore, supports tons of platforms and notifiers (RDBMS, S3, Dropbox, rsync, Hipchat, Zabbix) -- Ruby gem
Bacula - Open source backup tool, lots of downloads so I guess it's good I don't know -- C
Back in Time - Similar to TimeMachine, simple GUI backup program -- Python
Bareos (Backup Archiving REcovery Open Sourced) - Fork of Bacula with additional features -- C
bup - Uses the git packfile format, supports global dedupe, can use "par2" redundancy -- Python
DAR (Disk ARchive) - Better than tar, focuses on disks instead of tapes -- C++
ddrecover - This should be the first data recovery tool you use -- C
Deja Dup - GUI for duplicity -- C
Duplicati - Supports encryption and dedupe -- Mono
Duplicity - Encrypted bandwidth-efficient backup using the rsync algorithm -- Python
Elkarbackup - Comes as a ready to use VM, supports Linux and Windows -- PHP
Fpart - Packs file systems into "partitions" so you can do multi-threaded or multi-node rsyncs -- C
FSArchiver - Save the contents of a file system to a compressed archive, if one of the checksums doesn't match the file is lost, not the whole backup -- C
Grsync - GUI for rsync -- Windows OS X C
Mondo Rescue - Disaster recovery, supports tapes, disks, network and CD/DVD as backup media, multiple filesystems, LVM, software and hardware RAID -- C
Obnam - Snapshots, dedupe, encryption -- C
rdiff-backup - Combines the best features of a mirror and an incremental backup in a bandwidth efficient manner -- Windows OS X Python
Redo Backup and Recovery - Simple bare metal backup and restore, live CD -- Windows
Relax and Recover (REAR) - BMR, simple, integrates with commercial backup solutions -- shell
rsnapshot - Uses rsync and hard links, can keep multiple full backups available while using very little disk space -- OS X perl shell
SafeKeep - Superb project, uses LVM snapshots -- Python
SnapRAID - Backup program that also stores RAID parity information -- C
Unison - Multi-OS file sync tool, syncs from both sides, no master -- OS X
UrBackup - Supports Windows, has a web interface -- Windows C++
ZBackup - Globally deduplicating backup tool -- C
zpaq - Free incremental and journaling command-line archiver -- Windows OS X C++

Chef

Chef gets it's own category because they're MY links

Bento - Chef's collection of baseboxes configured to work with Packer and Vagrant, great for testing -- Ruby
Berkshelf - Like gem bundler for Chef cookbooks, manages dependencies -- Ruby gem
berks viz - Visualize cookbook and recipe dependencies for a cookbook -- Ruby gem built-in
Chake - Tool that helps you manage multiple hosts with chef-solo -- Ruby gem
chef-attribute-validator - Define, enforce, and handle violations of validation rules for Chef node attributes -- Ruby gem
chef-consul - Access Consul via Chef's node object -- Ruby
chef-guard - feature rich Chef add-on that protects your Chef server from untested and potentially dangerous cookbooks -- Ruby
chef-provisioning-docker - Official Chef solution for Docker provisioning -- Ruby
chef-relevant-tests - Runs Test Kitchen tests only on the parts of your code that changed (rather than the full suite) -- Ruby gem
chef-rewind - Monkeypatch some properties of a resource, during the compile phase, before chef-client actually starts the run phase, for debugging -- Ruby gem
chef-vault - Allow specified node(s) to dencrypt the contents of encrypted data bags -- Ruby gem
chef-whitelist - Library that enables easy rollout of changes to one or more hosts, by Etsy -- Ruby
ChefDK (Chef Development Kit) - Includes Berkshelf, Test Kitchen, ChefSpec, Foodcritic, Knife, Chef Zero, Ohai, and more -- Ruby
ChefSpec Examples - A billion code snippets and tests for ChefSpec -- Ruby
Chef Partner GitHub Repos - Official repo for tools, provisioners, and knife plugins from partners (VMware, GCE, Azure, AWS, etc) -- collections
Chef Sugar - Syntactic sugar for Chef by Seth V -- Ruby gem
Chef Supermarket (community) - Official community site for cookbooks -- various lang
Chef Supermarket (self-hosted) - Cookbook repository for Chef, can be hosted internally -- Ruby
Citadel - Cookbook to store secrets in AWS S3 buckets using EC2 and IAM -- Ruby
Cookbook Design Patterns - Likely the sanest cookbook architecture (Environment, Wrapper, Base, etc patterns) by JW -- article
Foodcritic - Chef linter and static code analysis -- Ruby gem
grocery-delivery - Utility for managing cookbook uploads to distributed Chef backends, by Facebook -- Ruby
Handlers - The official list of community written handlers (Airbrake, IRC, Campfire, etc) -- Ruby
Itamae - CM tool inspired by Chef, but simpler and lightweight, formerly LightChef -- Ruby gem
knife-backup - Knife plugin to help backup and restore a Chef server -- Ruby gem
knife-push - Official push jobs - action or a command to be executed against a subset of nodes -- Ruby
knife-sharp - Adds features such as data bag/environment/role sync & backup -- Ruby gem
Knife Plugins - The official list of community written plugins for Knife -- collection
motherbrain - Use knife to spin up one node? Nah, use this to create a whole environment, by Riot Games -- Ruby gem
omnibus - Create full-stack installers for your project -- Ruby gem
Policy File - Policyfile is a single document to specify the cookbooks and recipes that should be applied to node(s) -- official experimental
Ridley - Chef API client -- Ruby gem
ServerSpec - RSpec tests for your servers configured by Puppet, Chef or anything else -- Ruby
spiceweasel - Quickly automates the creation of whole Chef environments (batch loading) -- Ruby
tarball - Ruby-based resource provider to manage tarballs in Chef, by Ooyala -- Ruby
Test Kitchen - Automated testing for configuration management tools (mostly Chef) -- Ruby gem

Cloud File Sync and Sharing

Sync files to and share from public or private clouds - see also Backups

boar - Stores snapshots of directory trees in a local or remote repository, for BLOBs (pictures, videos , etc) -- Python C
Drive - Push or pull files to Google Drive via the command line -- Golang
git-annex Assistant - Sync folder(s) to any device (NAS, mobile, thumb, cloud, etc) via git -- C OS X mobile
lsyncd - Watches a local directory trees event monitor interface (inotify or fsevents) and kicks off an rsync when things change -- Lua
Mackup - Sync your Mac application settings to various cloud services or git -- Python OS X
Netcloud - Fork of and replacement for OwnCloud -- various lang Windows OS X
Pydio - Formerly AjaXplorer, AGPL license -- PHP
Skicka - Command line tool for working with Google Drive, by Google -- Golang
Seafile - Also offers a paid professional edition with more features, supports most platforms -- C
SparkleShare - Uses git under the hood, neat -- Windows OS X
Syncany - Supports tons of different protocols for the transfer (SCP, FTP, Samba, S3, etc) -- Gradle
Syncthing - Uses an ID rather than an IP address, share your ID with friends and go -- Golang
Tahoe-LAFS - Free and open decentralized cloud storage system -- Python

Collaboration Tools

ChatOps, code review, groupware, webmail, code sharing, and more

Barkeep - Code review tool, kinda sorta like GitHub -- Ruby
Citadel - Messaging, collaboration tools, and groupware - an all-in-one package -- C
Etherpad - Enter, save, and share text/code in a web browser -- JavaScript
FreeIPA - Identity, policy, and audit suite, think Active Directory for Linux (LDAP, CA, x509, DNS, Kerberos) -- various lang
gcalcli - CLI for Google Calendar -- Python pip
Haste / hastebin - Open source pastebin alternative for sharing code, can be installed locally / on-site -- JavaScript
Hubot - Chat bot that can do deploys, look up images, integrate with Google Maps, and tons of other stuff -- CoffeeScript
Kolab - Unified communication and collaboration system -- PHP
LDAP Account Manager (LAM) - Full featured LDAP management GUI, can manage almost anything -- PHP
Let's Chat - Self-hosted open source HipChat clone -- JavaScript
Mattermost - OSS Slack alternative -- Golang JavaScript
Mailtrain - Self hosted news letter e-mail app, similar to Mailchimp -- JavaScript
MultiRBL - SMTP blackhole lookup tools -- in-browser
MX Toolbox - SMTP blacklist lookup, header analysis, and more -- in-browser
OpenProject - Web-based project management system built on Ruby on Rails -- Ruby
osTicket - Routes inquiries created via email, web-forms and phone calls into a web-based customer support platform -- PHP
OTRS - Open source help desk software -- perl
OwnTracks - Self-hosted location tracking you can share - use for diaries, work orders, etc -- various lang mobile
Pandoc - Convert files from one markup format to another, supports a ton of formats -- Haskell
Phabricator - Suite of web-based software dev collaboration tools, and all-in-one project management tool -- PHP
RainLoop - Simple, modern & fast web-based email client -- PHP
Redmine - Project management webapp -- Ruby
Request Tracker - Bug tracking, help desk ticketing, customer service, workflow processes, change management and more -- perl
Review Board - Code review tool for multiple SCM systems -- Python
Roundcube - Browser-based multilingual IMAP client -- PHP
SOGo - Groupware that integrates with Microsoft, Android, and Apple products -- Objective-C OS X
Sovereign - Set of Ansible playbooks to deploy a suite of self-hosted apps (mail, colab, calendar, file sync, and more) -- Python
Staytus - Complete solution for publishing the latest info about issues with your web applications, networks or services -- Ruby
Sticky Notes - On-site / local pastebin -- PHP
Synergy - Share a single keyboard and mouse with multiple physical computers, only the old version is free now -- closed source Windows OS X
Taiga - Project management web application with agile/ scrum in mind -- Python CoffeeScript
TermRecord - Record and playback terminal sessions, outputs self-contained HTML -- Python
Your Own URL Shortener (YOURLS) - Lets you run your own URL shortener a'la TinyURL or bit.ly -- PHP
Zulip - Group chat, by Dropbox -- various lang mobile Windows OS X

Configuration Management

OS-level configuration management, Chef has it's own category because

Ansible - CM and orchestration, also can do provisioning -- Python
Ansible Galaxy - Community site for finding, reusing, and sharing Ansible content -- various lang
Automatic Server Hardening - Linux hardening cookbooks/manifests/playbooks for Puppet, Chef, and Ansible -- various lang
Blueprint - Reverse engineer a server configuration -- Python pip
BOSH - Cloud orchestration, supports Docker containers too -- Ruby
Boxen - Mac / OS X configuration management -- Ruby gem OS X
etckeeper - Stores /etc in version control, super easy config management -- various lang
hiera-eyaml - Backend for Hiera that provides per-value encryption of sensitive data within Puppet yaml files -- Ruby
Juju - Ubuntu focused but works on RHEL / CentOS now -- Golang
kitchen-puppet - Test Kitchen provisioner for Puppet -- Ruby
librarian-puppet - Bundler for Puppet, manages dependencies -- Ruby gem
Oxidized - Modern RANCID replacement, supports many platforms -- Ruby gem
puppet-lint - Check that your Puppet manifest conform to the style guide -- Ruby gem
puppet-profiler - Find out what's making your Puppet runs so slow -- Ruby gem
Puppet Dashboard - Web based dashboard for Puppet -- JavaScript
Puppet Forge - The official community repository of Puppet modules -- collection
puppet-module-skeleton - Skeleton modules for Puppet -- Ruby
r10k - General purpose toolset for deploying Puppet environments and modules -- Ruby gem
RANCID - (Really Awesome New Cisco confIg Differ) - Pulls and saves network device configs and saves them into a CVS, now supports git -- C
RANCID (Really Awesome New Cisco confIg Differ) with git Support - Monitor network hardware (switches, etc) and save their config into git, fork of the original RANCID -- perl
Rudder - Automation and compliance, uses CFengine -- Scala
Salt / Saltstack - Orchestration, server provisioning, and configuration management -- Python

Containers

Linux containers, container orchestration, provisioning, networking, PaaS, and related tools

appscale - Open source implementation of Google App Engine -- Python
Awesome Docker - Massive Docker collection -- collection
Bocker - Docker written in 100 lines of shell -- shell
boot2docker - Lightweight Linux distribution running Docker, packaged as an VM -- shell Windows OS X
cadvisor - Analyzes resource usage and performance characteristics of running containers -- Golang
Cloud Foundry - Open source PaaS by VMware and Pivotal -- Golang Ruby
crane - Docker orchestration -- Golang
Distribution - Docker Registry 2.0, supersedes docker-registry -- Golang
dockerfiles - Great little collection of pre-made Docker files -- various lang
DockerUI - Web interface for Docker -- JavaScript
Docker Compose - Define and run multi-container apps with Docker, previously known as fig -- Python
Docker Hub - Official Docker images for many projects -- various lang
Docker Toolbox - Docker Client, Machine, Compose, Kitematic, and VirtualBox in a single package -- various lang
Dokku - Docker powered mini-Heroku (PaaS) in around 100 lines of bash -- shell
drone - CI platform built on Docker -- Golang
dumb-init - Minimal init system for containers, by Yelp -- C
Fabric8 - Deploy and manage middleware components or long running Java programs running in a repeatable and controllable way -- Java
Ferry - Launch, run, and manage big data clusters without worrying about infrastructure -- Python
Flannel - Network fabric for containers via etcd -- Golang
Flocker - Docker data management for stateful services such as DBs -- Python
Flynn - PaaS built on top of Docker, can run stateful services -- Golang
Heapster - Container cluster monitoring and performance analysis for Kubernetes and CoreOS -- Golang
Hyper - Hypervisor-agnostic Docker engine -- Golang
Kitematic - App for managing Docker containers -- JavaScript Windows OS X
kubernetes - Open source orchestration system for Docker containers, by Google -- Golang
localkube - Set up a local Kubernetes instance on your laptop -- Golang
Logspout - Log router for Docker containers -- Golang
LXC (Linux Containers) - Runs an OS instance (sshd, cron, daemons, init, etc) within a container
OpenShift Origin - Docker + Kubernetes, the upstream for Red Hat's OpenShift 3.x -- Golang
Panamax - Containerized app creator with an open-source app marketplace hosted in GitHub -- various lang
pipework - SDN for Linux Containers -- various lang
Project Atomic - Super stripped down Linux OS designed to only run containers and nothing more, aka RHEL Atomic -- various lang
Rancher - Provides a complete platform for operating Docker in production -- various lang
Registrator - Service registry bridge for Docker, supports Consul, etcd -- Golang
rkt (Rocket) - New container system by the CoreOS guys -- Golang
Sandstorm - Download, install, and run apps in a container -- IDK but hashi
Shipyard - Composable Docker management toolkit -- Golang
ShutIt - All-in-one build system featuring Docker -- Python
systemd-nspawn - Spawn containers via systemd -- C article
Swarm - Docker-native clustering system -- Golang
Tsuru - Docker-based PaaS -- Golang
Ventriloquist - Combines Vagrant and Docker to give developers the ability to configure portable and disposable dev environments -- Ruby
Weave - Virtual network that connects Docker containers deployed across multiple hosts -- Golang
Zenoss Control Center - PaaS framework for deploying enterprise applications using Docker -- Golang

Dashboards and Data Visualization

Dashboards for monitoring, alerting, metrics and data visualization tools

Bigdesk - Live charts and statistics for Elasticsearch cluster -- JavaScript
Cachet - Create beautiful, responsive status pages -- PHP
Cacti - Web-based network monitoring and graphing tool designed as a front-end to RRDtool -- PHP
collectd3 - Beautiful D3 visualizations of system performance statistics -- JavaScript
Dashing - The exceptionally handsome dashboard framework -- Ruby gem
Dashing Widgets - Massive collection of widgets for Dashing -- collection
Facette - Time series data visualization and graphing software -- Golang
Flame Graphs - Stack trace visualizer by Brendan Gregg -- perl
Gource - Software version control visualization tool -- C++
Graphene - Graphite dashboard in D3 and Backbone -- JavaScript
Graphiti - Graphite dashboard using Ruby and Redis -- Ruby
Hygieia - Visualize near real-time status of the entire delivery pipeline, by Capital One -- Java
Hystrix Dashboard - Dashboard for Netflix's Hystrix tool -- Java
Kibana - Visualization component of the ELK stack -- JavaScript
ksar - Creates pretty graphs from sar output -- Java
logstalgia - Web site access log visualization tool, aka Apache Pong -- C++
gdash - Simple Graphite dashboard using Bootstrap -- Ruby
Grafana - Modern dashboard for Graphite -- JavaScript
Mozaik - Create beautiful dashboards using Node/React/D3 -- JavaScript
MRTG (Multi Router Traffic Grapher) - Still being updated -- perl
Nagdash - Dashboard / NOC screen for Nagios -- PHP
NagVis - Visualization suite for Nagios -- PHP
Nagiosgraph - Another visualization tool for Nagios data -- perl
Network Weathermap - Network visualization tool, create a "weather map" just like big ISPs use! -- PHP
pdash - web dashboard for linux using data mainly served by psutil -- Python pip
PNP4Nagios - Analyzes performance data provided by plugins and stores them automatically into RRD-databases -- PHP
redash - Web application that allows to easily query an existing database, share the dataset and visualize it in different ways -- various lang
ServerStatus - Display and monitor your servers statistics in a beautiful way -- C C++ JavaScript
Seyren - Alerting dashboard for Graphite -- Java
Stashboard - Status dashboard for APIs and software services -- Python
Tasseo - Dashboards using D3, HTML5, Bootstrap, and others -- JavaScript CoffeeScript
Tessera - Graphite dashboard in Python -- Python pip
Thruk - Web interface for Nagios, Icinga, Shinken and Naemon, can create SLA reports, has a mobile client -- JavaScript
Uchiwa - Dashboard for Sensu -- Golang
vnstati - Creates PNG images using vnStat data -- built-in

Distributed Systems Tools

DCOSes, service discovery, schedulers, and related tools for dynamic, warehouse-scale computing - see also HPC Tools

Aurora - Mesos scheduler for long running services and cron jobs, similar to Marathon -- Java
Bamboo - HAProxy auto configuration and auto service discovery for Marathon -- Golang
Chronos - Distributed, fault tolerant cron scheduler that runs on top of Apache Mesos -- various lang
crypt - Store and retrieve encrypted configs from etcd or Consul -- Golang
consul - Service discovery and configuration via DNS or HTTP, great for auto-scaling -- Golang
consul-do - Take action (eg: run a cron job) based on Consul leadership status -- Python
consul Tools - Official, includes consul-template and others -- various lang
Curator - ZooKeeper client wrapper and rich ZooKeeper framework, by Netflix -- Java
etcd - Distributed, consistent key-value store for shared configuration and service discovery -- Golang
eureka - AWS Service registry for resilient mid-tier load balancing and failover, by Netflix -- Java
fabio - Zero-conf load balancing HTTP(S) router for deploying microservices managed by Consul, by eBay -- Golang
fswatch - Cross-platform for watching files and taking action when they change -- C++
git2consul - Mirror git repos to Consul K/V stores -- JavaScript
gkv - Use git as a KV key/value store -- Ruby gem
Guard - Flexible framework to take action on file system change event -- Ruby gem
HAproxy - Open source software load balancer -- C
haproxyctl - Wrapper to talk to the HAProxy socket, as well as regular init (start stop restart) shit -- Ruby gem
Herd - A single-command bittorrent distribution system, based on Twitter's Murder -- Python
Hystrix - Library to stop cascading failures -- Java
Ignite - General-purpose in-memory platform for in-memory computing use cases -- Java
inotify - Watch file(s) for changes, take an action when the change occurs -- C
jespen - Call Me Maybe: Breaking distributed systems -- Clojure
Kong - Microservice / API management layer -- Lua
Mantl - Complete microservices infrastructure built using OSS tools by Cisco -- various lang yowza
Marathon - Mesos scheduler for "always on" jobs (eg: web services) -- Scala
marathon-consul - Take information provided by the Marathon event bus and forward it to Consul's KV tree -- Golang
MaxScale - General purpose DB query proxy, router, and load balancer, by MariaDB -- C
Mesos - Cluster manager and scheduler, similar to Google's Borg and Omega projects -- C++
mesos-consul - Automatically registers/deregisters services run as Mesos tasks -- Golang
Mesosphere - Apache Mesos schedulers for almost anything, commercial support is available -- C++
Myriad - YARN framework/scheduler for Mesos -- Java
nsq - Realtime distributed messaging platform / message queue -- Golang
Packetbeat - Distributed packet monitoring system that can be used for application performance management -- Golang
Redisson - Distributed and scalable Java data structures on top of Redis -- Java
Ringpop - Fault tolerant application-level sharding for Golang or Javascript -- JavaScript Golang
Seesaw - Load balancer based on Linux Virtual Server (LVS), by Google -- Golang
Serf - Decentralized solution for service discovery and orchestration -- Golang
SkyDNS - Service discovery via DNS for etcd -- Golang
SmartStack - Automated service discovery and registration framework, by Airbnb -- Ruby
Spring Cloud Config - Allows Java Spring to read config info from service discovery or similar source -- Java
Synapse - Service discovery framework by Airbnb -- Ruby
vulcand - Programmatically extendable proxy for microservices and API management -- Golang
Webjob - Downloads a program or script from a remote WebJob server, executes it, and sends back output to a server -- C
xCAT (Extreme Cloud Administration Toolkit) - Complete management solution for distributed systems (HPC, clouds, web farms, etc), supports almost every platform, by IBM -- various lang
Zookeeper - Distributed configuration service, synchronization service, and naming registry -- Java

Editors

IDEs, text & source editors, vim plugins, and similar tools

activate-power-mode - Activate POWER MODE and write code in style, an Atom plugin -- CoffeeScript
Atom - Superb text editor, created by GitHub -- CoffeeScript
Atom Vim Mode - vi/vim style controls for Atom -- CoffeeScript
Atom Linters - A collection of lint tools for the Atom editor -- various lang
Brackets - Modern editor that understands and focuses on web design, by Adobe -- JavaScript
LargeFile - vim plugin that automatically disables certain things so you can edit large (multi-gig) files faster -- vim
Light Table - Next-generation editor that gives you instant feedback -- Clojure
Lime - Open source API-compatible alternative to Sublime Text -- various lang
livedown - Live, in-browser markdown previews for vim and Sublime -- various lang
MacDown - Markdown editor and live preview for Mac -- Objective-C OS X
MacVim - Has far more features than the vim that's included with the OS -- C
Nuclide - Collection of packages for Atom to provide IDE-like functionality for a variety of programming languages and technologies, by Facebook -- JavaScript
Notepad++ - Killer GPL'ed text editor for Windows -- C++
OpenVim - In-browser vim tutorial -- JavaScript in-browser
percol - Interactive grep tool -- Python
Powerline - Provides various statues on the bottom of your session, flexible -- Python
Textmate - GUI text editor for OS X -- C++
UltiSnips - The ultimate snippet solution for vim -- Python
vim-json - A better JSON plugin for vim -- vim
vim-snippets - snipMate & UltiSnip snippets -- vim
Vimium - Chrome extension that provides vi/vim style shortcuts for navigation and control -- CoffeeScript Chrome
Vim Adventures - A game to learn vim using your browser -- in-browser
Vundle - Popular plug-in manager for vim -- vim
wasavi - vim/vi controls in browser text areas -- JavaScript Firefox Chrome
YouCompleteMe - Fuzzy-search code completion engine for vim -- Python

Git Tools

Tools for interacting with git and GitHub

BFG Repo-Cleaner - Scrub large blobs and sensitive data from git history -- Scala
Completion - Shell tab completion for git branch names -- shell
Gerrit - Web based code review and repo management for Git -- Java
git-fat - Like git-media but without the Ruby dependencies -- Python
GitHub Pull Request Builder Plugin (gprbp) - Jenkins plugin that allows certain comment strings to kick off builds or take other actions -- Java
GitLab - Kinda like an open source GitHub, has both a community and paid version -- Ruby
GitLab CI - CI that integrates with GitLab -- Ruby
GitRob - Scan repos for sensitive information -- Ruby
gitsome - Supercharged CLI with GitHub integration -- Python
GitUp - Maybe the best git GUI -- Objective-C
gitwatch - Automatically commit changes when specified files or directories are modified -- shell
Git Interfaces, Frontends, and Tools - Massive list on the official kernel.org wiki -- various lang
gkv - Use git as a KV key/value store -- Ruby gem
Gogs - Painless, self-hosted Git service written in -- Golang
hub - Official CLI for GitHub -- Golang
libgit2 - GitHub's official library for interfacing bindings for Ruby, Python, Go, and others -- various lang
myrepos - Flexible tool for managing many repos -- perl
Signing - Sign commits and/or tags using GPG keys to verify the identity of the commiter -- built-in

Graphics Stuff

Not everything happens in the browser or on the command line

Avidemux - Simple, all-in-one, GUI video editor and converter -- C++ Windows OS X
Blender - 3D graphics software for animated films, visual effects, art, 3D printed models, and more -- C Python Windows OS X
blockdiag - Generate simple block/sequence/activity/network diagrams from text files -- Python pip
CloudCraft - Create professional AWS architecture diagrams -- in-browser
Darktable - Photography workflow application and RAW developer, Adobe Lightroom replacement -- C OS X
draw.io - Free online flow chart maker / Visio alternative, can be self-hosted -- in-browser
FreeMind - OSS mind mapping software, great for brainstorming -- Java Windows OS X
GlyphSearch - Search for icons from Font Awesome, Glyphicons, IcoMoon, Ionicons, and Octicons -- collection
GIMP (GNU Image Manipulation Program) - Open source Adobe Photoshop replacement -- C
Graphviz - Graph visualization and flow chart software -- wacky license
Greenshot - The best Windows screenshot tool -- C# Windows
Inkscape - Open source vector image editor, Adobe Illustrator replacement -- C C++ Windows Mac
LICEcap - Capture an area of your desktop and save it to a GIF -- C Windows OS X
mac2imgur - Auto-upload screenshots to Imgur -- Swift OS X
maim - The most powerful and flexible Linux desktop screenshot tool -- various lang
Media Player Classic - Home Cinema (MPC-HC) - Open source media player for Windows -- C++ Windows
OpenShot - Video editing software, 2.0 will support other additional platforms -- Python Windows OS X
Pencil - Open source GUI prototyping and mockup tool, supports all platforms -- Windows OS X
Scribus - Open source desktop publishing (layout, typesetting, etc), Adobe InDesign alternative -- C++ Windows OS X
ShareX - One of the best screenshot/screencast capture and sharing tools for -- Windows OS X
Skitch - Feature-rich screenshot editing, sharing, and annotation tool Mac/OS X -- closed source
VisioCafe - The largest collection of free Visio stencils -- collection
VLC Media Player - Media (music, video, etc) player and streaming server -- C Windows OS X
yEd Graph Editor - Flowcharts and UML diagrams -- closed source

High Availability Clustering Tools

HA clustering tools including storage replication, failover, VIPs, and more

AN! Cluster Tutorial 2 - Building clusters with OSS software, very detailed -- article
Cluster Manager (cman) - Clustering framework that's built into RHEL/CentOS/Fedora -- built-in
Corosync - HA framework and cluster engine -- C
csync2 - General purpose cluster file sync tool -- C
DRBD (Distributed Replicated Block Device) - Mirror block devices to a remote system aka replication -- C
Ganeti - Wrappers around existing tools to make it easy to create HA clusters, by Google -- Python
HAproxy - Open source software load balancer -- C
haproxyctl - Wrapper to talk to the HAProxy socket, as well as regular init (start stop restart) shit -- Ruby
keepalived - Load balancing and high availability -- C
huptime - Zero downtime restarts of unmodified programs -- C
Linux-HA - Building blocks for high availability systems -- wiki-and-collection
LVS (Linux Virtual Server) - Linux-based load balancer, also includes the IPVS kernel module -- C
Pacemaker - HA resource manager -- C
rcron - cron redundancy and failover, ensures a job will only run on the "active" machine -- lost-to-the-internet C
rmanager - Resource group manager daemon for cluster services -- built-in
Seesaw - Load balancer based on Linux Virtual Server (LVS), by Google -- Golang
UCARP - VIP management using the CARP protocol -- C
Vippy - VIP management, written in node.js -- Javascript

HPC Tools

High performance computing for simulations, supercomputing, shared memory systems, and grid computing - see also Distributed Systems Tools

Clustered File System - Ceph, GlusterFS, Lustre, etc, take your pick -- various lang
HTCondor - Workload management system for compute-intensive jobs, formerly Condor
Maul Cluster Scheduler - Precursor to the Moab HPC Suite
MPI for Python (mpi4py) - Python bindings for the Message Passing Interface (MPI) standard
MPICH - High-performance and widely portable implementation of the Message Passing Interface (MPI) standard
MUNGE - Authentication service for creating and validating credentials, designed for HPC
MVAPICH2 - MPI-3 over OpenFabrics-IB, OpenFabrics-iWARP, PSM, and TCP/IP
OpenLava - IBM Platform LSF compatible workload scheduler that supports a variety of HPC and analytic applications -- C
OpenLava Web - Web GUI for OpenLava -- Python
OpenMP - API that supports multi-platform shared memory multiprocessing programming in C, C++, and Fortran -- article
OpenMPI - Popular Message Passing Interface (MPI) library -- C
Open Grid Scheduler - Formerly known as Sun Grid Engine -- C
OSCAR (Open Source Cluster Application Resources) - Makes it easy to create a Beauwulf-type HPC cluster
Rocks Cluster Distribution - Linux cluster distribution that enables end users to easily build computational clusters, grid endpoints and visualization displays
Slurm (Simple Linux Utility for Resource Management) - One of the mostly widely used schedulers
StarCluster - Toolkit for using AWS for HPC -- Python
TORQUE (Terascale Open-source Resource and QUEue Manager) - An updated and extended version of Portable Batch System (PBS)

Live CD Tools

Security, recovery, bootable USB/CD/DVD creation tools, diagnostics, and more

BlackArch Linux - Penetration testing Linux distro, based off of Arch Linux -- various lang
CAINE (Computer Aided INvestigative Environment) - Computer forensics on a live CD -- various lang
DBAN (Darik's Boot and Nuke) - SSD and spinning disk wiper -- various lang
Easy2Boot - Create multiple bootable Linux ISOs on the same USB drive -- Windows
GParted Live - Small, bootable ISO that contains gparted - great for resizing a non-LVM root file system -- C
Hiren's BootCD - Everything. Seriously. -- closed source Windows
Kali Linux - Penetration testing Linux distro -- various lang
Network Security Toolkit (NST) - Live CD that includes most tools in insecure.org's top 125 tools list -- various lang
Rufus - Create bootable USB flash drives -- Windows
Stresslinux - Hardware burn-in and stress testing -- various lang
System Rescue CD - System recovery CD that focuses on Linux system recovery -- various lang
Ultimate Boot CD (UBCD) - Tons of x86 diagnostic and stress test tools on a single CD -- closed source Windows
UNetbootin - Create custom, bootable USB Linux CDs -- Windows OS X
YUMI - Multiboot USB creator, Linux and -- Windows

Logging

Log management, analysis, and collection from any source

Adiscon LogAnalyzer - Slick web interface for syslog messages -- PHP
Apache Log Generator - Drag and drop to create Apache logging syntax -- in-browser
ElasticDump - Import / export tools for Elasticsearch -- JavaScript
Elasticsearch - Component of the ELK stack, used for super fast searches -- Java
Elasticsearch Copier (escp) - Tool to copy elasticsearch indexes, great for copying from prod to dev -- Golang
Elasticsearch Exporter - Small script to export data from one Elasticsearch cluster into another -- JavaScript
Eliot - Outputs causal chains of actions happening within and across process boundaries aka a logical trace of the system’s operation -- Python pip
Errbit - Tool for collecting and managing errors from other application, Airbrake API compliant -- Ruby
Filebeat - By Elastic, the next generation Logstash Forwarder -- Golang
Fluentd - Unified logging layer -- Ruby gem
Flume - Distributed, reliable, and available service for efficiently collecting, aggregating, and moving large amounts of log data -- Java
Graylog2 - Log capture and analysis -- various lang
Heka / hekad - Stream processing, can gather logs or performance metrics -- Golang
IRCcat - Send log messages and alerts to an IRC channel, can also use IRC to send commands -- Java
lnav - Advanced log file viewer for the small-scale, terminal/ncurses based -- C++
Log Courier - Enhanced fork of Logstash Forwarder -- Ruby
Logplex - Distributed syslog log router, uses Redis, by Heroku -- Erlang
logstash - Collect, parse, and store logs. A component of the popular ELK stack -- Ruby
logstash-forwarder - Formerly Lumberjack, forwards logs to centralized server(s), very lightweight -- Golang
Logster - Utility for reading log files and generating metrics to configurable outputs by Etsy -- Python
Logwatch - Monitor logs and send an e-mail when event(s) occur -- perl
multilog - Reads a sequence of lines from stdin and appends selected lines to any number of logs -- DJB
multitail - Monitor multiple log files in a single terminal window -- C
netconsole - Kernel module that sends kernel log messages (dmesg, etc) to a remote system without using syslog -- C
NXLOG - Universal log collector and forwarder, supports many formats/platforms/sources including Windows -- C Windows
Open Web Analytics (OWA) - Track and analyze how people use your websites and applications -- PHP
pgBadger - PostgreSQL log analyzer -- perl
Piwik - Web analytics platform with a killer UI -- PHP
Sentry - Application exception logging -- Python
Snoopy Logger - Logs commands that are executed and saves the information to syslog -- C
Snowplow - Web, mobile and event analytics -- Scala
swatch - Simple log watcher -- built-in
Webalizer - Web and FTP log analyzer -- C

Metrics

Collection, analysis, and storage of metrics, telemetry, and instrumentation data from almost any source - see also Dashboards and Data Visualization and Monitoring

collectd - Collects system performance statistics -- C
collectd Related Sites - Great tools that integrate with collectd -- collection
collectl - sar on steroids -- C
Diamond - Python daemon that collects system metrics and publishes them to Graphite (or similar), has an API -- Python
dim_STAT - Collects almost everything and stores it in a MySQL database, produces reports too -- C
FastForward - Flexible system event and metric forwarding agent by Spotify -- Ruby gem
Graphite - Store numeric time-series data and render graphs of the data on demand -- Python
Graphite Tools - Tools that work with Graphite -- collection
Heka / hekad - Stream processing, can gather logs or performance metrics, by Mozilla, based on Borgmon -- Golang
Heroic - TSDB by Spotify -- Java
InfluxDB - Distributed time series database with no external dependencies -- Golang
KairosDB - Time series DB written on top of Cassandra -- Java
Node-Bell - Real-time anomalies detection system for periodic time series -- JavaScript
OpenTSDB - Store and serve massive amounts of time series data without losing granularity -- Java
Prometheus - Metrics collection and storage, can trigger alerts when thresholds are breached, based on Borgmon -- Golang
RRDtool - High performance data logging and graphing system for time series data -- C
Scales - Metrics collection, written in Python -- Python pip
Skyline - Real-time anomaly detection system to enable passive monitoring of metrics without the need to configure thresholds -- Python
sysinfo_influxdb - Collect system metrics and store them in an InfluxDB server -- Golang

Monitoring and Alerting

Monitor stuff, send alerts, wake you up - see also Metrics

Adagios - Web based Nagios configuration interface -- HTML
Alerta - Distributed and de-coupled, requires MongoDB -- Python
bluepill - Simple process monitoring, written in Ruby -- Ruby
Bosun - Monitoring and alerting system written by Stack Exchange, based on Borgmon -- Golang
Cabot - Self-hosted, easily-deployable monitoring and alerts service - like a lightweight PagerDuty -- Python
check_mk - Extensions / plugins for Nagios -- C
check_mk Multisite - GUI for check_mk -- various lang
Daemon Tools - Service monitoring and management tools -- DJB
FastForward (ffwd) - Flexible system event and metric forwarding agent by Spotify -- Ruby gem
Flapjack - Alert routing and rollup so you don't get tons of alerts for large failures -- Ruby gem
Fully Automated Nagios - Easy to install, pre-packaged Nagios that includes the most-used tools and plugins -- various lang
Ganglia - Monitoring software that's focused on HPC / distributed clusters -- various lang
Icinga - Nagios fork, updated frequently -- various lang
Icinga2 - Complete re-write of Icinga -- various lang
jmxtrans - Connector between speaking to a JVM via JMX on one end and whatever logging / monitoring / graphing package -- Java
Kale - Monitoring stack by Etsy -- article
LibreNMS - GPL fork of Observium -- various lang
Monit - Includes tools to automatically take action when certain conditions are met (eg: restart a process when it dies) -- C
Monitorix - So lightweight that it can be used in mobile devices, aka Mikaku -- perl
Naemon - Modular Nagios fork -- various lang
Nagios - One of the most widely used OSS monitoring programs -- various lang
nagios-herald - Gives context to Nagios alerts, by Etsy -- Ruby
Nagios Exchange - Centralized repository of Nagios plugins, addons, extensions, etc -- collection
OpenNMS - Network monitoring, also supports configuration/asset management -- various lang
Open Monitoring Distribution (OMD) - Nagios bundled with the most popular plugins and tools -- various lang
pmacct - IP and network traffic accounting / monitoring -- C
PHP Server Monitor - Simple monitoring package that can use built-in public SMS gateways for notifications -- PHP
Pynag - Interface with Nagios via Python -- Python pip
Riemann - Aggregates events from your servers and applications with a powerful stream processing language, for distributed systems, similar to Borgmon -- Clojure
Sensu - Open source monitoring framework, cloud-focused -- Ruby
Sensu Plugins - Official community site for Sensu plugins -- various lang
Shinken - Compatible with Nagios -- various lang
StatsD - Monitoring in node.js by Etsy -- JavaScript
Tattle - Self service alerting and dashboard frontend for Graphite and Ganglia -- PHP
Uptime - Remote monitoring application using Node.js, MongoDB, and Twitter Bootstrap -- JavaScript
Xymon - Fork of Big Brother -- C
Zabbix - Stores monitoring data in a DB, has agents for almost every OS, can be a virtual appliance -- various lang
Zenoss Core - Supports Nagios plug-in format -- Python

Networking Tools

Hodge-podge of network tools

Angry IP Scanner - GUI network scanner, supports plugins, -- Java Windows OS X
aria2 - CLI for downloading HTTP/HTTPS, FTP, SFTP, BitTorrent and Metalink -- C Windows OS X
Awesome PCAP - Huge list of tools that work with PCAP captures -- collection
bbcp - Copies files using multiple TCP streams to greatly increase throughput -- C
bbFTP - Uses it's own transfer protocol, optimized for large file transfers -- C
BIRD Internet Routing Daemon (BIRD) - (Almost) fully functional IP routing daemon for Linux, supports tons of standard routing protocols -- C
BPF Tools - BSD Packet Filter (BPF) and pcap tools, by CloudFlare -- Python
Calico - L3 fabric that runs a vRouter on each node, supports containers -- Python
CERT NetSA Security Suite - Network flow analysis tools -- various lang
Cyberduck - GUI FTP, SFTP, WebDAV, S3 & OpenStack Swift browser for Mac and Windows -- itsaduck
Data Plane Development Kit (DPDK) - Data plane libraries and framework for fast packet processing -- C
dnscrypt-wrapper - Add dnscrypt support to any resolver, server-side dnscrypt proxy -- C
ExaBGP - The BGP swiss army knife of networking -- Python pip
fail2ban - Watches log files to ban IPs based on rules (too many failed logins, exploit attempts, brute force attacks, etc) -- Python
FBOSS (FaceBook Open Switching System) - FB's software stack for managing and controlling whitebox switches -- variouns lang
ftptop - Monitor FTP connections in real time -- built-in
ipcalc - CLI tool to calculate subnets, netmasks, IP ranges, broadcast addresses, and more -- built-in
iptstate - A top-like display of IP Tables state table entries -- built-in
geoiplookup - Uses the GeoIP DB and library to determine which physical country an IP or host originates in, includes PAM library -- built-in
GridFTP - Supports parallel streams, optimized for WANs, part of the Globus Toolkit -- C
hping3 - Create custom TCP/IP packets, very flexible -- built-in
lftp - Supports many protocols (FTPS, HTTPS, SFTP), scheduling, bandwidth throttling, scripting, and more - feature-rich -- C C++
moloch - Large scale IPv4 full PCAP capturing, indexing and database system -- JavaScript
mrsync (multicast remote sync) - Transfers from a master to many remote machines using Unix multicast sockets -- C
mTCP - High-performance user-level TCP stack for multicore systems -- C
Mulitpath TCP - Allows TCP to use multiple paths to maximize resource usage and increase redundancy -- neat
ncat - Improved netcat, written by the Nmap team -- C
netsniff-ng - High performance, zero-copy networking sniffer -- C
NfSen - GUI for and visualization nfdump -- perl
ngrep - Network grep -- C built-in
nmap - Classic port scanner -- various lang
nping - Create custom network packets -- C
Open vSwitch (OVS) - Production quality software switch -- C
Outages Dashboard - Outages mailing list's dashboard, tons of resources for internet outages -- collection
PFQ - Framework that allows efficient packets capture/transmission, in-kernel functional processing, and packets steering across sockets/end-points -- C
Quagga - Routing software suite, supports most routing protocols -- C
scapy - Interactive packet manipulation for Python -- Python pip
socat - netcat on steroids, supports serial devices -- C
spiped - Create encrypted pipes between socket addresses using PSKs, similar to ssh -L -- C
sslh - Protocol multiplexer, let multiple daemons listen on a single port -- C
SubBrute - Subdomain enumeration tool for penetration testers -- Python
tcpflow - TCP demultiplexer, each flow is stored in it's own file -- C++
Trigger - Network automation toolkit written in Python, created by AOL -- Python
UDR - UDT wrapper for rsync that improves throughput of large data transfers over long distances -- C++
WireShark - The classic network analyzer -- C
WireShark Tools - Superb list of network tools from the WireShark wiki -- collection
Zenmap - Official GUI for Nmap -- C Windows OS X
ZeroTier - Cloud / provider-agnostic private network backplanes, network virtualization -- C++ all platforms

Network Performance Analysis Tools

Load generation, benchmarking, profiling, and latency simulation tools for TCP/IP networks - see also Web and HTTP Performance Analysis Tools

ARGUS (Audit Record Generation and Utilization System) - Generates network activity reports -- C
Augmented Traffic Control (ATC) - A tool to simulate network conditions, by Facebook -- Python
bmon - Console based network monitor -- C
clumsy - Simulate poor network conditions on Windows -- C Windows
Comcast - Simulate crappy network connections -- Golang OS X
dummynet - Simulates/enforces queue and bandwidth limitations, delays, packet losses, and multipath effects -- C Windows
ESnet Fasterdata Knowledge Base - Provides proven, operationally sound methods for troubleshooting and solving performance issues -- collection hpcwisdom
EtherApe - Graphical network monitor, pretty output -- various lang
Flent - Python wrapper to run mutliple netperf/iperf3/ping in parallel, formerly netperf-wrapper -- Python
Flowgrind - Distributed TCP traffic generator -- C
iftop - top for network interfaces -- C
intrace - Enumerate IP hops using existing TCP connections -- C
iperf3 - Supports tuning of various parameters related to timing, protocols, and buffers -- C
iptraf-ng - Updated fork of iptraf -- C
mtr (my traceroute) - Combines ping and traceroute into a single program -- C
Muxy - Muck with your system and application context layers 4-7 -- Golang OS X
namebench - Hunts down the fastest DNS servers for your computer to use -- Python Windows OS X
nbwmon - Ncurses bandwidth monitor -- C
netatop - Kernel module for atop to watch and report on network packets -- C
NetHogs - Displays per-process bandwidth usage -- C C++
Network Link Conditioner - Simulate bandwidth, latency, and packet loss, by Apple -- closed source OS X
nfdump - Captures network flows including sFlow, NetFlow, NetFlow v9, ipfix, etc -- perl
nicstat - vmstat for network interfaces -- C
nload - Console application that monitors network traffic and bandwidth usage in real time, neat ASCII graphs -- C++
ntopng / ntop-ng - New version of the popular ntop tool -- C
netperf - The web page looks ancient but the software's still being updated! -- C
Paris Traceroute - Shows proper network topology when load balancers and load-balanced routers are used -- C
Saboteur - Network fault injection tool -- Python
Sloppy - Proxy server that slows down connections for testing -- Java Windows OS X
SmokePing - Network latency visualizer, written by the MRTG and RRDtool guy -- perl
ss - Socket statistics, a modern netstat -- built-in
Stanford Linear Accelerator Center - Network Monitoring Tools - MASSIVE list of network monitoring tools -- collection
tc - Built-in Linux kernel traffic control -- built-in
tcpdive - TCP performance analysis tool, implemented as SystemTap scripts -- C
tcpdstat - Get protocol statistics from tcpdump / PCAP files -- C
tcptrack - Console based connection tracker -- built-in
TCPWatch - TCP monitoring and logging tool -- Python pip
Tracebox - Detect middleboxes (NAT, transparent proxies, etc) in a network path -- C++
trickle - Userspace bandwidth shaper -- built-in
vnStat - Console based traffic monitor, supports statistic collecting -- C
WANem - WAN emulator for testing response over low bandwidth and/or high latency connections, also comes as virtual appliance -- various lang
Yconalyzer - Monitor and analyze TCP connections -- C++

Orchestration

OS and VM level orchestration as well as parallel SSH tools

Ansible - CM and orchestration, also can do provisioning -- Python
Archipel - Use XMPP push notifications to manage, supervise, and orchestrate VMs -- Objective-J
Batou - Define and perform automated service deployments -- Python pip
Capistrano - Use Ruby to run scripts/commands and push software via SSH, uses a Rake DSL -- Ruby gem
ClusterSHISH - Cluster SSH for Windows, works with PuTTY and OpenSSH for Windows -- closed source Windows
ClusterSSH - Make a change on many servers at the same time -- perl
csshX - Cluster SSH for OS X -- C
Fabric - Uses paramiko to implement a higher-level API for performing commands over SSH, particularly for deployment sysadmin tasks -- Python pip
KeyBox - Web-based SSH console that executes commands on multiple shells simultaneously and supports terminal sharing -- Java
KeyBox-OpenShift - KeyBox for OpenShift gears Java
ManageIQ - Upstream OSS project for Red Hat's CloudForms -- Ruby
Mass Parallel SSH (mpssh) - Simple parallel SSH -- C
mcollective (Marionette Collective) - Orchestration, can be used independently of Puppet -- Ruby gem
mussh - MUltihost SSH -- C built-in
OpenLMI (Open Linux Management Infrastructure) - Manage, monitor, and configure servers via API calls (instead of SSH), included in RHEL 7 -- various lang
orgalorg - Next generation parallel SSH tool because most other major ones are no longer maintined -- Golang
Overcast - VM orchestration and provisioning for DigitalOcean, Linode and Amazon, or locally using Vagrant + Virtualbox -- JavaScript
parallel - Execute jobs in parallel using one or more computers -- built-in
parallel-ssh (pssh) - Parallel version of OpenSSH tools - comes with prsync, pscp, pnuke, and pslurp too -- Python built-in
Parallel Distributed Shell (pdsh) - Kick off many SSH sessions in parallel -- C
paramiko - SSH2 protocol library for Python, provides both client and server -- Python pip
PyDSH - Python Distributed Shell, parallel SSH -- Python
RadSSH - Paramiko-based parallel SSH -- Python pip
Rex - Framework for server orchestration and to simplify system administration -- perl
Rubber - Capistrano/rails plugin that makes it easy to deploy/manage/scale to various service providers -- Ruby
Rundeck - Job scheduler and runbook automation, enable self-service access to existing scripts and tools -- Groovy
Salt / Saltstack - Orchestration, server provisioning, and configuration management -- Python
Spacewalk - Remote commands/orchestration, patch management, and more - the upstream for Red Hat Satellite -- various lang
Teleport - Front-end for teams, includes session capture and replay, auditing, 2FA, session sharing, and more -- Golang
tmux-cssh - Cluster SSH via tmux -- shell

Package Patch and Repository Tools

Repos, RPM/APT packages, packaging guidelines, patching, and patch management

apt-dater - Simple ncurses frontend for package management via SSH, also supports yum -- C
aptly - Swiss army knife for Debian repository management, has the ability to take snapshots for easy rollback -- C
AutoPkg - Packaging and distribution for OS X, great for managing many laptops -- Python OS X
CentOS Errata for Spacewalk (CEFS) - Import errata information from CentOS-announce into Spacewalk -- useit
CentOS Repositories - Large list of both official and unofficial CentOS software repositories -- collection
CentOS Software Collections (SCL) - Use multiple versions of software on a system without disturbing the system default version -- C
Copr - Automatic build system providing a package repository as its output, by Fedora -- C
cowbuilder - Package builder that uses copy-on-write (COW) to speed up the build process -- C
DNF - Package management system that will replace Yum in upcoming Fedora/RHEL/CentOS releases -- article
ELRepo - Repo that focuses on hardware related packages, supports RHEL and CentOS -- repo
Extra Packages for Enterprise Linux (EPEL) - Supports CentOS, RHEL, Scientific Linux, and Oracle Linux -- repo
Extra Packaging Guidelines and Policies for EPEL - Packaging guidelines, great even if not creating EPEL stuff -- readit
Fedora Packaging Guidelines - Excellent information that can be applied to CentOS & RHEL -- readit
fpm (Effing Package Management) - Build packages for multiple platforms (deb, rpm, etc) with great ease and sanity -- Ruby gem
fpm-cookery - Tool for building software packages with FPM -- Ruby gem
Homebrew - Tons of packages for Mac -- Ruby OS X
Koji - Software that builds packages for Fedora, can be used for other stuff too, uses mock -- C
Mock - Build packages in a simple chroot so you don't blow up your system -- C
mrepo - RPM repository management tool supporting ftp/http/sftp/rsync/rhn/you, formerly Yam -- Python
Munki - Managed software installation for OS X, great for managing laptops -- Python OS X
OStree - Tool for managing bootable, immutable, versioned filesystem trees (not really a package manager but...) -- thefuture C
Package Repository Manager (PRM) - OS-independent package repo creation and management tool -- Ruby gem
pkgr - Made deb or RPM packages out of any Ruby, NodeJS, or Go app -- Ruby
Pulp - Next generation repository management, a component of Red Hat Satellite 6 -- Python
Red Hat Software Collections (SCL) - Use multiple versions of software on a system without disturbing the system default version -- repo
reposync - Synchronize yum repositories to a local directory -- built-in
rpm-ostree - Take RPM packages and commit them to an OSTree repository -- C thefuture
RPM Fusion - Provides software that the Fedora Project or Red Hat doesn't ship -- repo
schroot - Allow non-root users to create chroot environments, great for package testing -- built-in
Spacewalk - Patch management, remote commands, and more - the upstream for Red Hat Satellite -- various lang
Tito - Tool for managing RPM based projects using git for their source code repository -- Python
yum-presto - yum plugin that provides support for downloading package deltas -- article
yum-security - Plugin to only install security updates -- built-in

Performance Analysis Tools

Non-specific and all-in-one performance monitoring tools - web, network, storage, and RDBMS have their own categories

atop - Supports both real-time and historical performance monitoring -- C
bwm-ng - Small and simple console-based live network and disk I/O bandwidth monitor -- C
Conky - Lightweight system monitor for X windows -- C++
dstat - Versatile replacement for vmstat, iostat, netstat and ifstat -- Python
Glances - Real-time performance monitoring, written in curses and Python -- Python
hazelnut - Python lib to parse /proc/meminfo -- Python pip
htop - top replacement, has a few additional features -- C
Linux Performance Observability Tools - Awesome graphic that shows you which tool to use, by Brendan Gregg -- the man
mem_logger.sh - Monitor a processes' memory usage over time -- shell
Munin - Historical performance monitoring to help determine when you server became "slow" -- perl
nmon - Provides both real-time and historical performance metrics -- C
NumaTOP - top for NUMA systems, shows hotspots, call chains, etc -- C
OProfile - System-wide statistical profiling tool -- C
perf - User-land performance analysis tool, a sampling profiler -- C
perf-tools - Uses perf and ftrace, includes iosnoop -- Brendan Gregg
Performance Co-Pilot (PCP) - System performance and analysis framework, included in RHEL 7 -- C
Phoronix Test Suite - Benchmarking and profiling suite, very feature-rich and versatile -- PHP
pidstat - vmstat type output for CPU, disk I/O, page faults, and more on a per-process basis -- built-in
pmap - Shell scripts for tracking memory usage using "pmap" -- shell
PowerTOP - Real-time power consumption on a per-process & per-thread basis, by Intel -- C++
ps_mem - Accurately reports core memory usage for a process -- Python
ptop - top/ntop-like task monitor written in Python -- Python pip
recap - Collects info from various standard utilities (free, sar, vmstat, etc) at specified intervals, by Rackspace -- various lang
saidar - ncurses based program for viewing system statistics -- built-in
slabtop - Tutorial on how to use slabtop, useful when you have no idea on how your RAM is being used -- article
smem - Reports memory usage based on proportional set size (PSS) instead of the usual resident set size (RSS) -- C
sysdig - Linux system exploration and troubleshooting tool with first class support for containers -- C++
SystemTap (stap) - Linux kernel tracing and performance analysis tool -- C C++
USE Method - Brendan Gregg's rosetta stone for performance analysis and tuning -- article

Provisioning Tools

OS provisioning, image creation, installation, bootstrapping, and lifecycle management

Box-Cutter - Hashicorp's community repo for Packer & Vagrant templates -- Ruby
Chef Baseboxes - Baseboxes provided by Chef, for Packer + Vagrant -- various lang
cloud-init - Configures settings the first time a system spins up (SSH keys, hostname, variables, etc) -- C
Cobbler - Provisioning system used in Red Hat's Satellite -- Python
Crowbar - Multi-purpose provisioning tool, created by Dell -- Ruby
edeploy - Tool to provision and update systems using trees of files instead of packages or VM images -- Python
Foreman - Provisioning and life cycle management -- Ruby Windows OS X
iPXE - GPL'ed version of PXE, official replacement for gPXE -- C
Katello - Candlepin + Pulp + Foreman, the core of Red Hat Satellite 6 -- various lang
Kickstart - The classic Red Hat tool -- various lang
Knife - See the Chef section for knife provisioning plugins -- Ruby gem
Metal as a Service (MaaS) - Ubuntu provisioning system -- various lang
netboot.xyz - Simple iPXE menu and installer -- shell
Overcast - VM orchestration and provisioning for DigitalOcean, Linode and Amazon, or locally using Vagrant + Virtualbox -- various lang
Packer - Automates VM creation for multiple platforms (VMware, AWS, etc) -- Golang
Pallet - Aims to solve the problem of providing a consistently configured running image across a range of clouds -- Clojure
Razor - Puppet provisioning software that handles bare metal hardware and virtual server provisioning -- Ruby
Terraform - Infrastructure provisioning using existing tools, supports many providers (AWS, Azure, DO, OpenStack, etc) -- Golang Hashicorp
Vagrant - Quickly spin up environments for local testing and development -- Ruby
Vagrant Plugins - A list of Vagrant plugins on the official Hashicorp wiki -- collection
Vagrant Manager - GUI to manage Vagrant boxes -- Windows OS X
vagrant-cachier - Cache BLOB downloads to reduce network usage -- Ruby
vagrant-host-shell - Simple plugin to run commands on the VM when it boots (think cloud-init) -- Ruby
vagrant-hostsupdater - Plugin to add your own /etc/hosts to the VM -- Ruby
vagrant-vbguest - Auto-install the latest VirtualBox tools at boot time (if necessary) -- Ruby
veewee - Easily (and repeatedly) build custom Vagrant base boxes, KVMs, and VM images -- Ruby
veewee-to-packer - translate veewee templates to Packer templates -- Ruby gem
Salt / Saltstack - Orchestration, server provisioning, and configuration management -- Python

Python Tools and Resources

Python stuff of note

2.7 and 3.x Differences - The differences between 2.7 and 3.x with examples, via HN -- article
Awesome Python - Very large list of Python resources -- collection
bpython - Killer interface for the Python interpreter -- Python
Common Python Mistakes - Link and discussion on HN -- article
Easy-Python - Collection of Python resources that "you didn't know you would need" -- collection
Faker - Generate fake data easily -- Python pip
Google Python Style Guide - Google's Python style guide -- article
IPython - Interactive Python shell and the kernel for Jupyter -- Python
Jinja2 - Templating language for Python -- Python pip
Jupyter - The language-agnostic parts of IPython -- Python
Micro Python - Python for microcontrollers, embedded, and small memory systems -- Python
PyPI (Python Package Index) - Software repo for Python packages, like Ruby gems or a RPM repo -- collection
Python Reference - A collection of useful scripts, tutorials, and other Python-related things -- collection
PyPy - Python alternative with advance features (JIT compiles, sandboxing, etc) -- Python
python-prompt-toolkit - Library for building interactive command lines -- Python pip
Requests - The best HTTP library -- Python pip
sh - Library that allows you to call any program (shell command) as if it were a function -- Python pip
virtualenv - Tool to create isolated Python environments -- Python pip
virtualenvwrapper - Extensions to virtualenv -- Python pip
xlwings - Replace your Excel VBA code with Python -- Python pip

Python Programming Tutorials

Tutorials, exercises, and challenges for learning Python. I have no idea how good/bad these are

46 Simple Python Exercises - Focuses on Python 3
500 Lines - Many full Python programs written in 500 lines or less, great for beginners
Codecademy - Codecademy's online Python course
CodingBat - Practice problems
Coursera - Online Python courses at various institutions
Dive Into Python 3 - Free ebook
edX - Python courses at edX
Google Python Class - By the GOOG
importpython's Python Book List - Includes both free and pay, ebooks and physical
Intermediate Python - Free ebook
Invent with Python - Series of free ebooks, includes Automate the Boring Stuff with Python, recommended books
Learn Python, Break Python - Free ebook
MIT Open Courseware - Introduction to Computer Science and Programming - Focuses on Python
MIT Open Courseware - A Gentle Introduction to Programming Using Python - Final project is a Tetris game in Python
MIT Open Courseware - Objects in Python - Python tuples, lists, and dictionaries, as well as the concept of mutability and how to avoid problems relating to it.
MIT Open Courseware - Python Tutorial - Python tutorial for people familiar with basic programming concepts
New Coder - Python exercises
Online Python Tutor - 100% in-browser
Programming Praxis - Programming exercises, many posted solutions are in Python
Python Challenge - A riddle in Python
Python for Infomatcis - Free ebook
Python for You and Me - The 2.x version is linked on the main page
Python Practice Projects - Several practice exercises
Python 2.x Tutorial - For 2.x, part of the official documentation
Python 3.x Tutorial - From the official documentation
Quiz and Learn Python - Designed for mobile devices
r/dailyprogrammer - Programming exercises, includes Python
r/learnpython - Subreddit for beginners, be sure to check the wiki too
Supporting Python 3 - Free ebook that focuses on porting to Python 3.x
Think Python: How to Think Like a Computer Scientist - Awesome free ebook
Tutorials Point's Python Tutorial - Another one!

RDBMS and SQL Tools

Tools for interacting with and related to the major DBs and SQL

Adminer - GUI for database management in a single PHP, formerally phpMyAdmin -- PHP
Flyway - Version control for DB schemas, supports most DBs -- Java
HeidiSQL - GUI SQL DB browser and editor -- Windows OS X
Large Hardon Migrator (LHM) - Live, online MySQL migrations -- Ruby
Liquibase - Tracking, managing, and applying database schema changes, SVN for DBs -- Java
MaxScale - General purpose DB query proxy, router, and load balancer by MariaDB -- C
mycli - CLI for MySQL and derivates with auto-completion and syntax highlighting -- Python
mydumper (MySQL Data Dumper) - Much better than mysqldump, works in parallel -- perl
MySQL sys schema - Collection of views, functions and procedures to help MySQL administrators get insight into MySQL usage -- SQL
MySQL Utilities - Official collection of MySQL tools -- various lang Python
MySQL Workbench - The official MySQL GUI for admins, devs, DBAs, and architects -- various lang
Oracle TPT Scripts - Tab completion for Oracle -- SQL
orchestrator - MySQL replication topology management and visualization tool, GUI -- Golang
Percona Toolkit for MySQL - Percona's special toolkit -- various lang
pgcli - Postgres CLI with autocomplete and syntax highlighting -- Python
pgloader - Fast data loader for PostgreSQL -- Lisp
pgweb - Web-based PostgreSQL DB browser -- Golang
pg_repack - Remove bloat from tables and indexes without using an exclusive lock -- C
Phinx - Database migrations in SQL or PHP -- PHP
Postgres-XL - Scale-out version of PostgresSQL -- C
PostgREST - Create a REST API for any Postgres DB -- Haskell
PostgreSQL GUI Tools - A huge list on the official wiki -- collection
Presto - Distributed SQL query engine for big data, by Facebook -- Java
rdbms-subsetter - Generate a random sample of rows from a relational database that preserves referential integrity, great for using production data for testing/dev -- Python
rlwrap - Add history and tab completion to SQLplus -- C
SchemaSpy - Analyze the metadata of a schema and visualize it in HTML -- Java
Sequel Pro - MySQL management GUI for Mac -- OS X
SQLite - Self-contained, serverless, zero-configuration, transactional SQL database engine, great for testing -- C
sqlmap - Detect and exploit SQL injection flaws, pen testing tool -- Python
SQL Fiddle - Write and test SQL -- in-browser
wal-e - Simple continuous archiving for PostgreSQL -- Python
WebScaleSQL - Huge scale MySQL with contributions from Facebook, Google, LinkedIn, and Twitter -- C C++
WWW SQL Designer - Designing RDBMS schemas features saving, exporting to XML, and SQL script creation, free SaaS version here -- JavaScript

RDBMS Performance Analysis Tools

Load generation, benchmarking, telemetry, and profiling for various RDBMS platforms

Anemometer - MySQL slow query log monitor and analyzer, by Box -- PHP JavaScript
db_STRESS - Database benchmarking and stress-testing kit, supports most DBs -- C
HammerDB - Load testing and benchmark tool, supports most DBs -- Tcl
innotop - "top" for MySQL -- NOTE: beware of exposing your password -- perl
MySQLtuner-perl - Analyzes a MySQL installation and provides suggestions to increase performance -- perl
MySQL Performance Analyzer - Open sourced by Yahoo -- Java
mytop - Another "top" for MySQL -- perl
Open PostgreSQL Monitoring (OPM) - Includes a web console, nice GUI -- JavaScript
Percona Monitoring Plugins - Some of the best mySQL plugins -- various lang
Percona Toolkit for MySQL - Percona's internal tools -- various lang
pg_activity - htop for PostgreSQL -- Python
pg_view - PostgreSQL monitoring, supports ncurses, console, and JSON output -- Python pip
pgbench-tools - PostgreSQL benchmarking suite -- various lang
PGObserver - Killer PostgreSQL monitor, includes dashboard -- Python
Silly Little Oracle Benchmark 2 (SLOB2) - Stresses and benchmarks Oracle DBs, works at the RDBMS layer -- various lang
shawn-s - Superb Reddit post on performance evaluation and tuning -- article
Swingbench - Oracle load generator -- closed source
SysBench - Evaluates OS parameters that are important for DBs, does not require a DB to be installed -- C
Tsung - Distributed stress tester, also supports stress testing DBs -- Erlang
Use the Index, Luke - SQL indexing and tuning for developers -- article

Regular Expressions

regex checkers, creators, evaluators, debuggers, and tutorials

Debuggex - Online regex debugger -- in-browser
Learn regex the Hard Way - The hard way -- tutorial
perlretut - perl-focused but very useful for all regex -- article
Refiddle - Online, supports JavaScript, Ruby, and .NET only -- in-browser
regex101 - Online regex tester and debugger, supports multiple languages -- in-browser
RegexOne - Learn regular expressions with simple, interactive examples -- tutorial
regexper - Regex visualizer using railroad diagrams, great for debugging -- in-browser
RegExr - Another online regex tool that includes cheat sheets, examples, and community-contributed expressions -- collection
RegularExpressions.info - THE BEST regex site -- collection
Regular Expressions - A Gentle User Guide and Tutorial - The easy way -- tutorial
RexV.2 - Online Regex evaluator, supports multiple languages -- in-browser
Rubular - Online Ruby-only regex evaluator -- in-browser
txt2re - Regex generator, recommended -- in-browser
txt2regex - Converts human sentences to regex, written in bash -- shell

Ruby Tools and Resources

Ruby toolbox full of junk

Awesome Ruby - A collection of awesome Ruby libraries, tools, frameworks and software -- collection
Bundler - Manage Gem dependencies using simple config files -- Ruby gem
did_you_mean - Suggestions for typos in Ruby code -- Ruby
fog - Library for communicating with clouds -- Ruby gem
Omniref - A better search site for Ruby documentation -- collection
Pry - IRB alternative, very feature-rich, great for debugging -- Ruby gem
Rake - Make / Makefile-like build utility -- Ruby gem
rbenv - Alternative to RVM -- shell
replicate - Dump and load relational objects between Ruby environments (eg: prod and dev) -- Ruby gem
RSpec - Behavior-driven development (BDD) testing framework -- Ruby
RuboCop - Static code analyzer that enforces guidelines -- Ruby gem
Ruby Gems - The Ruby package manager, gems are essentially libraries -- Ruby gems
Ruby Toolbox - Trillions of Ruby projects, categorized -- collection
RVM (Ruby Version Manager) - Install, manage, and work with multiple Ruby environments -- Ruby

Ruby Programming Tutorials

Tutorials, exercises, and challenges for learning Ruby. I have no idea how good/bad these are

Basic Ruby - Videos and exercises
Codecademy - Ruby course at Codecademy
Coderbyte - Programming challenges
Codewars - More challenges!
Coursera - Online Ruby courses at various institutions
edX - Ruby courses at edX
exercism.io - Challenges with peer review!
Introduction to Programming with Ruby - By Tealeaf Academy
Learn Ruby the Hard Way - Have fun with this
r/dailyprogrammer - Programming exercises, includes Ruby
r/learnruby - Subreddit for beginners
Rubeque - Super easy to hard level challenges
Ruby Koans - The most highly recommended tutorial
Ruby Monk - Free, interactive tutorials to help you discover Ruby idioms in your browser
Ruby Quiz - Weekly programming challenge
Ruby Warrior - Coding challenges WARNING sound, but you can turn it off
Treehouse Ruby Courses - Recommended
Try Ruby - Interactive tutorial in your web browser
Tutorials Point - Interactive online course

Secret Management

Password, private key, and API key storage and management tools

blackbox - Safely store secrets in Git, by Stack Exchange -- shell
Diceware - Neat IRL passphrase generator -- doitirl
GPG (GNU Privacy Guard) - The original! Store em in text files and encrypt -- C pro
GRC Password Generator - Generates 63 bit passwords -- in-browser
Keybase - Upload your public key and find other people's public key via their social media user name(s) -- in-browser
KeeFox - Auto-fill website logins using KeePass as a source, like LastPass -- C# Firefox
KeePass - Lightweight, easy to use, GUI password manager, runs on most platforms -- C# Windows
Keepass2Android - Compatible with KeePass 2.x -- Android
KeePassDroid - Open source version of KeePass 1.x for Android -- Android
KeePassX - Alternative to KeePass, requires QT -- C++ Windows OS X
KeeWeb - Unofficial web and desktop front-ends to KeePass -- JavaScript
Keywhiz - A system for distributing and managing secrets (API keys, certificates, etc), by Square -- Java
kpcli - Command line interface / CLI for KeePass -- perl
lastpass-cli - CLI for LastPass -- C
msktutil - Keytab client for a Microsoft Active Directory environment -- built-in
One-Time Secret - Create links that self-destruct after a single viewing, great for sharing passwords -- Ruby
pass (passwordstore) - Uses GPG at it's core, supports tracking password changes in git -- shell
passff - Addon for interacting with the a pass aka passwordstore repository -- Firefox
Password Gorilla - Written in -- Tcl/Tk
Password Pusher - Links to passwords expire after a certain number of views and/or time has passed, RoR app -- Ruby
Password Safe - Designed by Bruce Schneier himself -- bam
pwd.sh - Script to manage passwords in an encrypted file using GPG -- shell
pwgen - Password generated, included in most Linux distros -- built-in
RatticDB - Web-based password management, includes an API, great for teams or companies -- Python
scrypt - Super secure against hardware brute-force attacks, is also a part of/module for most programming languages, by tarsnap -- C
TeamPass - Collaborative password management using the LAMP stack -- PHP
Vault - Tool for storing secrets (API keys, passwords, certs, etc) by Hashicorp -- Golang
webpasswordsafe - Very powerful, designed "for the enterprise" -- Java
xca - OSS all in one PKI -- C++
zxcvbn - Password strength estimator, written by Dropbox, operates in a browser window -- CoffeeScript in-browser

Security Tools

Misc security tools

AIDE (Advanced Intrusion Detection Environment) - File integrity checker, alternative to Tripwire -- various lang
Armitage - GUI for Metasploit -- Java
Awesome Honeypots - Curated collection of honepots and honeypot resources -- collection
bro - Framework for network analysis and security monitoring -- C++
chkrootkit - Rootkit checker, best used from a live CD -- C
CIS Linux Benchmarks - Linux OS hardening guides, superb! -- collection
ConfigServer Security and Firewall (CSF) - Stateful Packet Inspection (SPI) firewall, Login/Intrusion Detection and Security application for Linux servers -- various lang
Cryptkeeper - System tray applet that manages EncFS encrypted folders -- C
dcfldd - Enhanced dd with security and forensics features -- C
Dshell - Network forensic analysis framework, written by the US Army -- Python
EncFS - Encrypted file system in user space via FUSE -- C++
Forensics Wiki - Digital forensics wiki, tons of tools and information -- wiki
FTimes - System baselining and evidence collection tool -- C
fwknop (FireWall KNock OPerator) - Single Packet Authorization (SPA) aka next-generation port knocking -- various lang
hashcat - World's fastest CPU password cracker / password recovery -- C
Information Security Cheat Sheets and Checklists - An assortment of IS checklists and cheat sheets -- collection
Jailkit - chroot toolkit -- C
Lynis - Auditing and hardening tool, supports most Unix-like operating systems -- shell
Metasploit - Classic exploit framework -- various lang
nmap Scripting Engine (NSE) - Tons of scripts for nmap -- various lang
oclHashcat - World's fastest CPU + GPU password cracker / recovery software -- C
OpenSCAP - NIST Certified SCAP 1.2 toolkit -- C
OpenVAS - Vulnerability scanner, forked from the now closed-source Nessus scanner -- C
Open Web Application Security Project (OWASP) - Focus on web application security -- organization
Oracle Database Attacking Tool (ODAT) - Open source penetration testing tool that tests the security of Oracle databases remotely -- Python
OS X Auditor - Forensics tool for Mac -- OS X JavaScript
OSSEC - Host based intrusion detection system (HIDS), supports most Unix-like OSes -- C Windows OS X
pfsense - The best firewall software, supports appliances and live CDs -- C
Prey - Open source anti-theft software for almost all platforms -- shell Java mobile
Red October - Go server for two-man rule style file encryption and decryption -- way cool
Rootkit Hunter - Compares hashes of important files with known good hashes that are stored in online databases -- perl shell
Samhain - HIDS, file integrity checker, rootkit detection, log file monitoring, and more -- C
ScoutBot - Automated network scanner for Raspberry Pi -- various lang
Security Onion - Linux distro for IDS, NSM, and log management -- various lang
Security Technical Implementation Guide (STIG) - Guides to securing almost every application, by the US military -- collection
Snort - The classic network intrusion prevention system (NIPS) -- C
Spiderfoot - Automate the process of gathering intelligence about a given target -- Python
sudosh2 - Records all keystrokes and output and can play back the session as just like a VCR -- C
URLquery - Free service to scan a URL for web-based malware -- in-browser
usbkill - Kill switch that takes action when a USB device is connected -- Python
Tripwire - File integrity checker and monitor, replacement for the now closed-source Tripwire -- C
VirusTotal - Allows you to upload a file and have it scanned by tons of virus scanners -- in-browser
ZMap - Scanner designed for large address spaces -- in-browser

Shell Scripting and Tools

Shell scripting tutorials and neat shell tools

Advanced Bash-Scripting Guide - By the Linux Documentation Project (LDP) -- tutorial
Awesome dotfiles - All kinds of . files -- collection
autojump - Small database of directories that you visited in the past, used to quickly navigate complex directory structures -- Python
Awesome Shell - Massive collection of shell tools -- collection
Babun - Pre-configured Cygwin with many more features and a better design -- various lang
BashGuide - Targeted at beginners -- wiki
bashrc PS1 Generator - Drag and drop to create a custom PS1 prompt -- in-browser
Bash Hackers Wiki - Human-readable bash documentation so you don't have to dig through the man page -- wiki
Bash Pitfalls - Common errors that bash programmers make -- wiki
bro pages - Simplifed man pages and examples -- collection
cheat - create and view interactive cheatsheets on the command-line -- Python
comm - Display lines that two files have in common (eg: the opposite of diff) -- built-in
CommandlineFu - Killer code snippets -- collection
CRUSH (Custom Reporting Utilities for SHell) - Killer toolset for working on delimited data, by Google -- C
Cygwin - GNU shell and tools for Windows -- C Windows
dotfiles by Paul Miller - Beautiful and flexible Mac terminal configuration files and utilities -- shell OS X hawt
dotfiles - Unofficial guide to dotfiles on GitHub -- collection
Environment Modules - Dynamic modification of your shell environment using modules -- Tcl Windows
Explain Shell - Enter a command-line to see the help text that matches each argument -- in-browser
fu - CLI for CommandlineFu.com, allows for easy searches -- Python
fzf - Command line fuzzy finder, supports tmux/bash/zsh -- Golang
Grymoire awk Tutorial - Easy to understand awk tutorial -- tutorial
gt5 - A "du browser" in curses, handy for finding large files -- shell
icdiff - diff tool that highlights the differences -- Python OS X
maybe - Allows a dry run of almost any Linux binary -- Python pip
moreutils - "Collection of the unix tools that nobody thought to write long ago when unix was young" -- neat
notify - Send a SMS to your phone from the CLI -- JavaScript Shell
pigz - Parallel gzip for multi-processor/core systems -- C
pv - Shows the progress of data as it flows through a pipe -- built-in
ShellCheck - Checks shell scripts for common mistakes, essentially a linter -- in-browser
sysadmin-util - A collection of small but useful utilities -- perl
tldr - Simplified and community-driven man pages, cuts out a lot of cruft -- collection
The Art of Command Line - Master the command line, in one page -- collection
Unix Toolbox - A collection of Unix/Linux/BSD commands and tasks for advanced users -- collection

Software Development Tools

Build systems, stubs/mocks, CI/CD, cheat sheets, and other

ack2 - grep-like tool designed to search source code -- perl
afl-fuzz (American Fuzzy Lop) - One of the best fuzzers -- C
ag (aka The Silver Searcher) - Source code searching tool, a better grep -- C
Bazel - Google's build system -- Java
Bento - Links to tutorials based on subject (programming, sysadmin, protocols, standards, etc) -- collection
Buildbot - CI framework -- Python
CRIU Checkpoint/Restore in Userspace - Freeze a process, save it to disk, then resume it later -- insane
cwrap - Wrappers for creating test scenarios and faking behavior/ stubbing, mostly network focused, by the Samba guys -- C
deployinator - Etsy's deployment framework -- Ruby gem
Design Patterns - Wonderful collection of design patterns with examples -- collection
DevDocs - Documentation browser for almost every API -- collection
dev-setup - Automated setup scripts for tools like Sublime Text, AWS, Spark, Android dev, and more -- collection
Go (GoCD) - Go continuous delivery platform by ThoughtWorks -- Java
Google's Technical Development Guide - Hands on, free, self-paced courses to help you develop your programming skills -- collection
Guard - Flexible framework to take action on file system change event -- Ruby gem
Gulp - Built system / toolkit that helps you automate time-consuming tasks in your development workflow -- JavaScript
Jenkins - The most popular CI orchestration tool, supports a billion plugins -- various lang
jenkins-job-dsl (Jenkins Job DSL Plugin) - Groovy-based DSL for writing Jenkins jobs -- Groovy
Jenkins job-config-history Plugin - Tracks changes to system and job configurations -- Java
JSON Server - Full fake REST API for quickly prototyping and mocking in 30 seconds -- JavaScript
LearnXinYMinutes - Super fast tutorials for almost every programming language -- collection
Mastif Visualizer - Visualizer for the Valgrind's Mastiff utility -- C++
Microsoft Cloud Design Patterns - Ignore the cloud and Azure stuff and it's a great reference for general software dev -- collection
MockServer - Web server to remotely or locally mock HTTP/HTTPS and similar -- Java
mountebank - Stub downstream resources for testing, supports HTTP HTTPS SMTP TCP -- JavaScript Windows OS X
Ninja - Small build system with a focus on speed -- Python
OverAPI - Large collection of cheat sheets for almost anything -- collection
PatchELF - Simple utility for modifying existing ELF executables and libraries -- C
PRoot - chroot, mount --bind, and binfmt_misc without privilege/setup -- C
Proxygen - Modern C++ HTTP library, by Facebook -- C++
REST-assured - Java DSL for testing of REST services -- Java
RocksDB - Library that provides an embeddable, persistent key-value store for fast storage - by Facebook -- C++
rpm-maven-plugin - Package artifacts as a RPM -- Java
Software Engineering Blogs - A curated list of software engineering blogs -- collection
SonarQube - Platform and dashboard for managing code quality -- Ruby Java
Sonatype Nexus - Software / binary artifact storage -- Java
Spinnaker - Cloud-focused CI/CD system by Netflix -- Python
Valgrind - Tool suite that includes cache profilers, heap profiles, thread race condition checkers, and more - a CPU-level emulator -- C
watchman - Watch files and take action when they change (eg: kick off the CI system), by Facebook -- C
WireMock - Flexible stubbing and mocking services -- Java

SSH Tools

Misc SSH stuff - see also Terminal Tools and SSH Clients for clients and Orchestration for parallel SSH tools

Advanced SSH Config - Enhances ssh_config file capabilities -- Python pip
autossh - Automatically restart SSH sessions that stop passing traffic -- C
Ballast (Balancing Load Across Systems) - Balance user load across SSH servers based on configured policies -- C
Corkscrew - Tunnel SSH through HTTP proxies -- C
Keychain - Manage SSH and GPG keys, acts as a frontend to ssh-agent, only enter passphrase once per reboot -- shell
Match - Creates a conditional block, great for controlling actions on a per-user and/or per-host basis in sshd_config -- built-in
Mosh (Mobile Shell) - Remote shell that supports roaming (client IP address changes) and intermittent connectivity, by MIT -- C++
rssh - Restricted shell for SSH, only allows scp, sftp, rdist, rsync, and cvs -- C
scponly - Shell that only allows incoming SCP, supports chroot -- C
ssh-chat Instead of a shell you get a chat prompt -- Golang
ssh-ldap-helper - Store public keys in LDAP -- built-in
SSHFS - Mount remote file systems using a SSH tunnel -- built-in
sshmuxd - SSH jumphost style proxy -- Golang
sshrc - Sources the ~/.sshrc on your local computer after logging in remotely -- shell
SSH Guard - Think fail2ban for SSH -- C
SSH Power Tool (sshpt) - Execute commands and upload files to many servers simultaneously via SSH without using pre-shared keys -- Python pip
storm - CLI and GUI tool to manage your SSH connections (add, delete, list, search) -- OS X

SSL Tools

SSL, TLS, CAs, and similar tools for interacting with HTTPS and SSL certificates - see also Web and HTTP Tools

BadSSL.com - Test various clients (browsers, etc) against bad SSL configs -- in-browser
BoringSSL - Google's fork of OpenSSL, does not guarantee API and ABI compatibility -- C
Calomel SSL Validation - Score and analyze the strength and settings of a SSL connection -- Firefox
cipherscan - Find out which SSL ciphersuites are supported by a target -- Python
Dogtag Certificate System - PKI component of FreeIPA, by Fedora -- C
duraconf - A collection of hardened configuration files for SSL/TLS services by Jacob Appelbaum -- collection
etcd-ca - Simple CA by the CoreOS guys -- Golang
HSTS (HTTP Strict Transport Secuirity) - Forces browsers to interact with a site by only using HTTPS -- article
Lemur - Broker between CAs and environments providing a central portal for developers to issue TLS certificates with 'sane' defaults -- Python
Let's Encrypt - Free SSL certs from a real CA -- in-browser
LibreSSL - OpenBSD's fork of OpenSSL, Linux compatible -- C
Mozilla Server Side TLS - Mozilla's extensive server side TLS configuration guide -- wiki
Mozilla SSL Configuration Generator - Generate SSL configs for Apache, Nginx, ELB, HAproxy and more -- in-browser
nogotofail - Spot and fix weak TLS/SSL connections and sensitive cleartext traffic, by Google -- Python
Qualys SSL Server Test - Evaluates and provides recommendations for the SSL settings of any web site -- in-browser
Server Name Indication (SNI) - Think vhosts for SSL -- article
sslconfig - CloudFlare's Internet facing SSL cipher configuration -- collection
SSLsplit - Transparent and scalable SSL/TLS interception -- C
sslyze - Fast and full-featured SSL scanner, written in Python -- Python OS X
SSL Checker - Type in a domain name and it will dump info about its cert -- in-browser
SSL Decoder - Decodes a SSL connection and displays certificate information, CLI -- PHP
SSL Decoder - Same as above but web based -- in-browser
stunnel - Create TLS tunnels for existing services (eg: telnet, nc, etc) -- C

Storage Tools

The storage junk drawer

ATA Secure Erase - Send a signal to an ATA drive to perform a hardware-based erase -- article
Clonezilla - Disk image/cloning tool, supports most file system types -- perl shell
CockroachDB - Open source version of Google's Spanner storage system -- thefuture Golang
CrystalDiskInfo - S.M.A.R.T. GUI tool for Windows -- closed source Windows
EnhanceIO - SSD caching, in the mainline Linux kernel, a fork of Facebook's Flashcache project -- C
Fog - Cloning tool -- C++
FreeNAS - BSD-based NAS, supports ZFS -- C
fs-cache - Modern NFS client-side caching -- built-in
Linux-IO Target (LIO) - Create and share iSCSI, FC, FCoE, and other storage targets on Linux VMs -- built-in
Linux Journal - Linux Swap Space - Superb article about Linux swap, includes some tuning parameters -- article
lsblk - List block devices -- built-in
lvcache - Simple wrapper to help you create and manage LVM caches -- Python
ncdu - ncurses version of "du" -- built-in
OpenFiler - Linux-based NAS, supports most protocols and storage types -- C
Parted Magic - Resize, grow, shrink, clone, recovery, wiping, benchmarking, and more. Supports Linux and Windows file systems -- Windows
scrub - Supports many disk-wiping standards including military / government grade wipes -- built-in
snapper - CLI tool to manage Btrfs snapshots, snapshot timelines, and more -- various lang
System Storage Manager (SSM) - Generic CLI for managing all types of storage (DM, LVM, multipath), added in RHEL 7 -- built-in
Tomb - zsh wrapper script for cryptsetup + gpg + LUKS volumes -- shell
VeraCrypt - OSS successor to and fork of TrueCrypt, supports Linux, Windows, and Mac -- C C++

Storage Performance Analysis Tools

blktrace - mount -t debugfs debugfs /sys/kernel/debug && blktrace -d /dev/md2 -o - | blkparse -i - -- article
Bonnie++ - The classic, still updated -- built-in
Connectathon Test Suite - NFS stress testing and benchmarking tools -- various lang
DPACK (Dell Performance Analysis Collection Kit) - Load generation, reporting, profiling -- closed source
findswappers - perl script that identifies swapped processes -- perl
fio - Supports 19 different I/O engines (sync, mmap, libaio, posixaio, etc), very powerful -- C
Fnotifystat - Dumps the file system activity in a given period of time -- C
IObench - Generic I/O stress tool that's a part of dim_STAT -- C
iometer - Multi-platform, by Intel -- C++
ioping - Monitor I/O latency in real time -- C
iorate - Originally written by EMC, now open source -- C
iotop - top for I/O requests, displays information on a per-process basis -- Python
IOzone - Supports NFS, still being updated! -- C
Threaded I/O Tester (tiobench) - Threaded I/O tester -- C

Terminal Tools and SSH Clients

Fancy SSH clients, terminal sharing, and similar tools

Bitvise SSH Client - Feature-rich SSH & SFTP client for Windows, free for individual use -- closed source Windows
Byobu - An enhanced version of the "screen" utility -- shell OS X
ConnectBot - Open source SSH client for Android -- Java Android
Guacamole - Clientless (in-browser) remote desktop gateway, supports VNC and RDP -- various lang
iTerm2 - Killer terminal replacement for Mac -- OS X -- Objective-C
KiTTY - PuTTY fork with additional features -- Windows
MobaXterm - Tabbed SSH, VNC, and RDP client for Windows, free for personal use -- closed source Windows
mRemoteNG - Open source, tabbed, multi-protocol, remote connections manager -- Windows
MTPuTTY (Multi-Tabbed PuTTY) - Multiple PuTTY sessions in a single window -- Windows
NoVNC - Client-less VNC in a web browser, uses HTML5 and WebSockets -- in-browser
PuTTY - The classic SSH client -- Windows
reptyr - Reparent a running program to a new terminal -- C
SuperPutty - Allows the PuTTY SSH client to be opened in tabs -- Windows
tmate - Instant terminal sharing, a tmux fork -- OS X
tmux - Alternative to GNU screen, also used for terminal sharing -- C
tmux-cssh - Cluster SSH for tmux -- shell
tmux Resurrect - Persists tmux environment across system restarts -- shell
WinSCP - The well-known SCP client -- C Windows
x2go - One of the best remote-desktop-over-SSH clients -- Windows OS X
Xshell - SSH client for Windows, free for personal use -- closed source Windows

Tracing and Debugging

OS and process-level tracing and debugging tools - see also Performance Analysis Tools for tools suited to performance profiling

bcc - Next generation, Linux 4.x kernel tracing tools, uses eBPF (Extended Berkeley Packet Filters) -- C
[CRIU](Checkpoint/Restore in Userspace)](http://criu.org/Main_Page) - Freeze a process, save it to disk, then resume it later -- insane
kdump - Linux kernel dump facility (where to save it, what to save, etc) -- C
ktap - Another lightweight kernel tracing tool for Linux -- C
Linux Trace Toolkit - Next Generation (LLTng) - Linux kernel tracer and profiler, lower overhead than System Tap -- C
ltrace - Library call tracer -- built-in
ltrace Tutorial - ltrace tutorial by Red Hat -- article
lttng-analyses - Great front-end to LLTng -- various lang
OpenSnoop - Continually monitor for file opens -- shell
pstore - Save kernel crash info in a platform-specific persistent memory so data is not lost (eg: disks failed so write dump to NVRAM instead) -- article
Record and Replay (rr) - Record the failure once, then debug the recording deterministically, by Mozilla -- C
strace - System call tracer for user space processes -- built-in
SystemTap (stap) - Linux kernel tracing and performance analysis tool -- C C++

Two Factor Authentication

Universal 2nd Factor (U2F) is the successor to two-factor authentication / TFA / 2FA and multi-factor authentication / MFA

Two Factor Auth (2FA) - Web sites that do and don't support 2FA, organized by category -- checkit collection
Authy SSH - Easy 2FA for SSH servers -- shell
CentOS 7 2FA - VPN with CentOS 7 + FreeRADIUS + SSSD + Google Authenticator -- tutorial
FreeOTP - Open source fork of Google Authenticator, by Red Hat -- C mobile
Google Authenticator - Official project, supports Android, iOS, and even has a PAM module -- C
Nitrokey - Open source thumb drive for authentication -- various lang
pam-u2f - PAM module for auth via U2F compatible devices, by YubiKey -- C
yubico-pam - PAM module for use with YubiKey devices -- C

Virtualization

OS-level virtualization and emulation

DOSbox - Open source DOS emulator, great for running old games or utilities -- C C++
KVM (Kernel Virtual Machine) - The one, the only -- C
kvm-tools - CLI tools for managing qemu-kvm domains -- C
KVM Management Tools - Great list of KVM management tools on the KVM wiki, updated frequently -- collection
libvirt - Open source API, daemon and management tool, used with many virtualization solutions -- C
QEMU (Quick EMUlator) - Also supports hardware emulation (SPARC, RISC, etc) -- C
Oracle VM VirtualBox - Easy, simple virtualization -- C C++ Windows OS X
oVirt - Virtualization management platform, the upstream for Red Hat Enterprise Virtualization (RHEV) -- Java
phpVirtualBox - Web front-end for VirtualBox -- PHP
virt-manager - KVM / Xen / LXC GUI -- Python
WINE - Compatibility layer for running Windows apps on POSIX-compliant OSes -- C OS X
Xen - It's a hypervisor! -- C
XenServer - Successor to Xen Cloud Platform (XCP) -- C
xhyve - Lightweight OS X virtualization based on bhyve -- C OS X

VMware Tools

Mostly unofficial VMware tools and some PowerCLI scripts

Compliance Checker for vSphere - Provides detailed compliance checks against vSphere hardening guidelines, official tool -- closed source
Flings - Tons of a little apps written by VMware engineers, worth exploring -- closed source? various lang
Onyx - Do something in vSphere and it will create a PowerCLI script to do that thing that you just did -- closed source PowerShell Windows
open-vm-tools - OSS alternative to VMware Guest Tools -- C
RVtools - Killer GUI for viewing information about your VMware environment -- closed source .NET Windows
RVtools Export - Wrapper script to save daily snapshots of your environment using RVtools -- PowerShell
Sexigraph - Graphite-based visualization appliance for Sexilog -- various lang
Sexilog - ELK stack virtual appliance designed for vSphere / VMware ESXi logs -- various lang
vCheck - Get an overview of a new environment or check the health of an existing one -- PowerShell
vDisk Informer - Check vDisks alignment and see if they have wasted space -- closed source Windows
vGhetto Script Repository - Various scripts from virtuallyGhetto -- various lang
VMTurbo Virtual Health Monitor - Monitoring and reporting tool -- closed source
VMware Community PowerPack - A variety of scripts from Virtu-al.net and now other blogs such as ict-freak.nl and ntpro.nl -- PowerShell
VMware on Github - VMware's Github repos -- various lang
VMware Sample Exchange - Code samples & scripts by both VMware and the community -- various lang
vSphere Health Check Report - Reports a massive amount of information, by VMware -- closed source perl
vSphere Mobile Watchlist - Monitor VMs on your phone -- closed source mobile

VPN Tools

Mostly server-side tools

n2n - L2 over L3 VPN that uses a peer-to-peer architecture -- C
OpenVPN - The one and only -- C
Pritunl - Distributed enterprise VPN server built using the OpenVPN protocol, supports Google sign-in -- Python
SoftEther - Perhaps the best VPN software out there -- C
sshuttle - Transparent proxy server that works as a poor man's VPN, forwards over SSH, supports DNS tunneling -- Python OS X
strongSwan - IPsec-based -- C
tinc - Simple, multi-platform VPN -- C
WireGuard - In-kernel VPN server that's simple, performant, and provides next generation cryptography -- C

Web and HTTP Tools

RPC is dead, long live RPC - see also SSL Tools

API Blueprint - Supports bindings/plugins for many APIs -- various lang
Awesome JSON - It's the new XML -- collection
Awesome Nginx - A collection of resources covering Nginx, Nginx + Lua, OpenResty and Tengine -- collection
curlish - Improved curl, includes cookie management and OAuth 2.0 support -- Python pip
Fiddler - HTTP/HTTPS debugging proxy for any browser, system or platform -- closed source
Geocities-izer - Make any HTML web page look like a Geocities page -- in-browser sweeeeeeet
gor - Capture and replay HTTP traffic for testing -- Golang
gRPC - High performance RPC via HTTP/2, by Google -- C
h2c - HTTP/2 CLI client, curl/wget type behavior and other advanced features -- Golang
h2i - Go's interactive HTTP/2 console debugger, send raw frames, etc -- Golang
Hamms - Simulate/create connection failures, malformed response data, slow servers, fat headers, and more! -- Python
Hipache - Distributed HTTP and websocket proxy, supports load balancing -- JavaScript
htaccess Snippits - Huge collection of common and useful .htaccess snippets, please contribute -- collection
httpdiff - Perform the same reuqest against two HTTP servers and diff the results -- Golang
httpie - curl replacement with many new features -- Python
htty - A console application for interacting with web servers -- Ruby gem
Huginn - Build agents that perform automated tasks for you online -- Ruby
JSON Server - Full fake REST API for quickly prototyping and mocking in 30 seconds -- JavaScript
jq - Command line JSON processor and manipulator -- C
localtunnel - Share a HTTP/web service on your local development machine without messing with DNS and firewall settings -- JavaScript Windows OS X
mitmproxy - Intercept, modify, replay and save HTTP/S traffic - even edit flows on the fly -- Python pip
mountebank - Stub downstream resources for testing, supports HTTP HTTPS SMTP TCP -- JavaScript Windows OS X
ng-admin - Add an AngularJS admin GUI to any RESTful API -- JavaScript
nghttp - CLI HTTP/2 client, similar to curl/wget and more -- C
ngrok - Reverse proxy that creates a secure tunnel from a public endpoint to a locally running web service and captures & analyzes all traffic over the tunnel for later inspection and replay -- rocks Golang
OpenResty - Turn nginx into a non-blocking API server -- C
OWASP Zed Attack Proxy (ZAP) - Pen testing too that focues on web applications -- Java
PageKite - Makes HTTP servers or SSH publicly available on any server -- Python
POSTman - Create and share API and HTTP requests, great for testing and sharing -- Chrome
Pushpin - Proxy server that adds WebSockets to existing request-response APIs -- C++
RapidJSON - Super fast JSON parser and generator -- C++ Windows
Redirect Detective - See the complete path a redirected URL goes through -- in-browser
Repose - REST proxy, solutions to API tasks such as auth, rate limiting, API validation, HTTP logging, and much more -- Java
Resty - CLI REST client you can use in shell/bash/zsh pipes -- shell
Swagger - A JSON format/standard that describes a RESTful API -- various lang
tengine - A distribution of Nginx with some advanced features, by Alibaba -- C
tortilla - Easily wrap web APIs -- Python pip
Tyk - API gateway -- Golang
Varnish - Caching HTTP accelerator -- C
vcr - Record and play back HTTP sessions -- Ruby gem
w3af - Web application attack and audit framework, OSS vun scanner -- Python

Web and HTTP Performance Analysis Tools

Load generation, benchmarking, and profiling for SaaS, webapps, and HTTP(S)

Awesome Web Performance Optimization - Collection of web performance optimization (WPO) tools, articles, and more -- collection
apachetop - top for Apache -- perl
Betwixt - Web debugging proxy with a Chrome DevTools look -- JavaScript
boom - HTTP load generator written in -- Golang
django-debug-toolbar - Panels that display profiling information about the current request/response -- Python pip
django-speedbar - Shows a breakdown of page loading time -- Python pip
Chrome DevTools - Many built-in tools for performance analysis -- mostly OSS
Gatling - HTTP, JMS, and WebSocket load generator -- Scala
GoAccess - Real-time web log analyzer and interactive viewer that runs in a terminal and/or dashboard -- Windows OS X
Firefox Developer Tools - A full list of built-in Firefox developer tools including performance tools -- various lang
flask-debugtoolbar - The Django Debug Toolbar ported to Flask -- Python
FunkLoad - Functional and load web tester -- Python pip
h2load - HTTP/2 and SPDY load generation tool, part of the nghttp2 suite -- C
HATop - ncurses top for HAProxy -- Python
httperf - HTTP load generator, originally created, by HP -- C
httping - Simple program that "pings" a URL and shows response time -- C
JChav - Visualize JMeter output -- Java
JMeter - Designed to load test functional behavior and measure performance, written in Java -- Java
Locust - Load generation tool written in Python that allows you to define user behavior -- Python
ngxtop - Real time top for nginx -- Python
PageSpeed Insights - Analyzes the content of a web page, then generates suggestions to make that page faster, by Google -- in-browser
PageSpeed Module - Open-source server modules that optimize your site automatically (nginx and Apache), by Google -- various lang
peep - Heap inspector for live memcached instances -- Ruby
phantomas - JS web performance metrics collector and monitoring tool -- JavaScript
redis-faina - Query analyzer that parses Redis' MONITOR command for counter/timing stats about query patterns, by Facebook -- Python
Siege - CLI based HTTP load generation tool, supports basic authentication, cookies, and HTTPS -- C
Speed Tracer - Helps you identify and fix performance problems in your web applications, by Google -- Chrome
Tsung - Distributed stress tester, also supports stress testing DBs -- Erlang
vegeta - HTTP load testing tool, written in Go -- Golang
Web Page Test - Free website speed test from multiple locations around the globe using real browsers (IE and Chrome) and at real consumer connection speeds -- in-browser
Web Performance Today - About an article a week, good stuff -- article
wrk - Multi-threaded CLI-based HTTP load generation tool -- C
wrk2 - Fork of wrk that fixes the "coordinated omissions problem" -- C
YSlow - Analyzes web pages and why they're slow based on Yahoo!'s rules for high performance web sites, customizable -- JavaScript
wtop - Another top for Apache logs -- Python pip
Varnish Dashboard - Realtime dashboard for Varnish cache servers -- JavaScript
Zipkin - Distributed tracing systems for SaaS and webapps, by Twitter, based on Google's Dapper -- Scala

Misc Tools and Utilities

Everything else

Awesome - Top level list of awesome lists -- collection
AutoHotKey - Automate input (desktop and web forms, data entry, keybinds, etc) -- C++ Windows
Awesome AutoHotKey - A collection of AutoHotKey scripts and libraries -- various lang
conserver - Virtual console server with many features (multi-user, console log history, etc) -- C
f.lux - Changes your screen from blue light to yellow light when the sun sets to tell your brain it's night time -- closed source OS X Windows
Google Advanced Operators for Web Search - Search modifiers for more accurate results, by Google -- collection
googler - Google search, news, and site search from the terminal, slick -- Python
inxi - "a full featured system information script" (hardware info, etc) -- shell
Mjolnir - Automation for OS X, think AutoHotKey for Mac -- C OS X
Quick Look Plugins - Collection of plugins for Quick Look in the Mac Finder -- various lang OS X
runit - UNIX init scheme with service supervision, great for containers, sysvinit replacement -- C
runwhen - Utilities for running commands at particular times, cron on steroids -- C
supercron - Cron on steroids -- Python pip
supervisord - Process control, kinda like an init replacement but not really -- Python
Unix Rosetta Stone - The one and only resource for a mixed Linux/Unix environment -- translator

Table of Contents

Tools by Category

IT News

Linux News and Articles

Linux Message Boards and Forums

Asset Management

AWS Tools

Backups

Chef

Cloud File Sync and Sharing

Collaboration Tools

Configuration Management

Containers

Dashboards and Data Visualization

Distributed Systems Tools

Editors

Git Tools

Graphics Stuff

High Availability Clustering Tools

HPC Tools

Live CD Tools

Logging

Metrics

Monitoring and Alerting

Networking Tools

Network Performance Analysis Tools

Orchestration

Package Patch and Repository Tools

Performance Analysis Tools

Provisioning Tools

Python Tools and Resources

Python Programming Tutorials

RDBMS and SQL Tools

RDBMS Performance Analysis Tools

Regular Expressions

Ruby Tools and Resources

Ruby Programming Tutorials

Secret Management

Security Tools

Shell Scripting and Tools

Software Development Tools

SSH Tools

SSL Tools

Storage Tools

Storage Performance Analysis Tools

Terminal Tools and SSH Clients

Tracing and Debugging

Two Factor Authentication

Virtualization

VMware Tools

VPN Tools

Web and HTTP Tools

Web and HTTP Performance Analysis Tools

Misc Tools and Utilities

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