Gems for iobuffer

https://github.com/tarcieri/iobuffer

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

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

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/

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

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

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/

High-speed Dirac codec

http://www.diracvideo.org/

Smart Common Input Method platform

http://www.scim-im.org

SCIM add-on to input various symbols with customisable on-screen pad

http://www.scim-im.org/

ANSI C version of the SciMark2 benchmark

https://math.nist.gov/scimark2/download_c.html

Build tool alternative to make

https://scons.org/

Tiny shell that only permits scp and sftp

https://github.com/scponly/scponly/wiki

Converts the output of "vidcontrol -p" to PNG

Converts the output of "vidcontrol -p" to text

Multi-screen window manager

http://www.gnu.org/software/screen/

Small and lightweight screen(1) wrapper

https://sourceforge.net/projects/screenie/

Various X related scripts

https://cgit.freedesktop.org/xorg/app/scripts

Open Document Cataloging Project

http://scrollkeeper.sourceforge.net/

SCReenshOT - command line screen capture utility

https://github.com/resurrecting-open-source-projects/scrot

Interpreter for several adventure games

https://www.scummvm.org/