Fluent event collector

http://fluentd.org/

GDSII reader and writer

http://rubyforge.org/projects/gdsii/

Fast, Enjoyable HTML Parser for Ruby

https://github.com/hpricot/hpricot

Simple callback-based HTTP request/response parser

https://github.com/tmm1/http_parser.rb

New wave Internationalization support for Ruby

https://github.com/ruby-i18n/i18n

iconv wrapper library

https://github.com/ruby/iconv

Gems for iobuffer

https://github.com/tarcieri/iobuffer

Simple logging utility for outputting messages

https://github.com/ruby/logger

Parser / Dumper for LTSV

https://github.com/condor/ltsv

Library for handling money and different currencies

http://rubymoney.github.io/money/

Gems for MessagePack

https://msgpack.org/

Framework-agnostic way to render logic-free views

https://github.com/mustache/mustache

YAML parser and emitter

https://github.com/ruby/psych

Fast Markdown converter for ruby based on discount

https://dafoster.net/projects/rdiscount/

RDoc produces HTML and command-line documentation for Ruby projects

https://ruby.github.io/rdoc/

Builds manuals

https://rtomayko.github.io/ronn/

Framework to implement robust multiprocess servers

https://github.com/treasure-data/serverengine

Setup signal handler which dumps backtrace of running threads

https://github.com/frsyuki/sigdump

Pseudo IO class from/to String

https://github.com/ruby/stringio

Fast strptime engine

https://github.com/nurse/strptime

Ruby utilities for exporting SVN repo to git

https://github.com/nirvdrum/svn2git

Thread-safe collections and utilities for Ruby

https://github.com/ruby-concurrency/thread_safe

Daylight-savings aware timezone support for Ruby

https://tzinfo.github.io/

IANA Time Zone database for TZInfo

https://tzinfo.github.io/

Daylight-savings aware timezone support for Ruby

https://tzinfo.github.io/

Provide classes to handle Uniform Resource Identifiers

https://github.com/ruby/uri

HTTP server toolkit

https://github.com/ruby/webrick

Streaming JSON parsing and encoding library for Ruby

https://github.com/brianmario/yajl-ruby

Fast program launch menu for X Window System

http://www.boomerangsworld.de/cms/tools/runner.html

Restricted User SHell, providing limited remote access to resources

https://puszcza.gnu.org.ua/software/rush/

Language with a focus on memory safety and concurrency

https://www.rust-lang.org/

Experimental Rust compiler front-end for IDEs

https://rust-analyzer.github.io/

Language with a focus on memory safety and concurrency (FreeBSD version)

https://www.rust-lang.org/

Generate Rust bindings from C (and some C++) code

https://github.com/rust-lang/rust-bindgen

Generate C bindings from Rust code

https://github.com/eqrion/cbindgen

Clone of the terminal emulator rxvt modified to support Unicode

http://software.schmorp.de/pkg/rxvt-unicode.html

Subset of a well-known texture compression scheme

https://github.com/divVerent/s2tc/wiki

FUSE filesystem that uses Amazon S3 as a backing store

https://github.com/archiecobbs/s3backer

FUSE-based file system backed by Amazon S3

https://github.com/s3fs-fuse/s3fs-fuse

nsupdate utility with the GSS-TSIG support

https://www.isc.org/software/bind

Free SMB/CIFS and AD/DC server and client for Unix

https://www.samba.org/

Ninja-compatible build tool written in C

https://github.com/michaelforney/samurai

Virtual file system for sandboxing

https://github.com/bazelbuild/sandboxfs

API for access to scanners, digitals camera, frame grabbers etc

http://www.sane-project.org/

Stand-Alone shell combining many common utilities

http://members.tip.net.au/~dbell/

Wrapper around libsass

http://libsass.org/

Build tool for Scala projects

http://www.scala-sbt.org/

Scala Programming Language

http://www.scala-lang.org/

Scan_ffs recovers lost disklabel

Small man page generator

https://git.sr.ht/~sircmpwn/scdoc/