This C library contains some essential string manipulation functions and more, like escaping special characters.

This library provides a C99 implementation of the Message Queuing Telemetry Transport (MQTT) publish-subscribe messaging protocol.

This library is a C99 implementation for AWS event stream encoding, a binary format for bidirectional client-server communication.

The purpose of libfixposix is to offer replacements for parts of POSIX whose behaviour is inconsistent across *NIX flavours.

The UDUNITS-2 package provides support for units of physical quantities. Its three main components are:

1. udunits2lib, a C library for units of physical quantities;

2. udunits2prog, a utility for obtaining the definition of a unit and for converting numeric values between compatible units; and

3. an extensive database of units.

Calcurse is a text-based calendar and scheduling application. It helps keep track of events, appointments and everyday tasks. A configurable notification system reminds user of upcoming deadlines, and the curses based interface can be customized to suit user needs. All of the commands are documented within an online help system.

Khal is a standards based console calendar program, able to synchronize with CalDAV servers through vdirsyncer. It includes both a CLI and a TUI named 'ikhal'.

Gcal is a program to calculate and print calendars on the command-line. Calendars can be printed in 1-month, 3-month or whole-year views. In addition, eternal holiday lists can be generated for many countries, which can be complemented by user-made lists of fixed dates to make an agenda. Gcal can also calculate astronomical data, such as the phases of the moon, and supports alternative calendar formats: Julian, Gregorian, Islamic, Chinese and more.

LibHdate is a small library for the Hebrew calendar and times of day, written in C, and including bindings for C++, pascal, perl, php, python, and ruby. It includes two illustrative command-line programs, hcal and hdate, and some snippets and scripts written in the binding languages.

Date is a header only C++ library that extends the chrono date algorithms library for calendar dates and durations. It also provides the <tz.h> library for handling time zones and leap seconds.

By default, date2name gets the modification time of matching files and directories and adds a datestamp in standard ISO 8601+ format YYYY-MM-DD at the beginning of the file or directory name.

Libical is an implementation of the iCalendar protocols and protocol data units.

gsimplecal is a lightweight calendar application written in C++ using GTK. Launched once, it pops up a small calendar applet, launched again it closes the running instance. It can additionally be configured to show the current time in different timezones.

ccal is a command line program which writes a Gregorian calendar together with Chinese calendar to standard output. Its usage is similar to the cal program. In addition to console output, it can also generate Encapsulated Postscript and HTML table outputs for use in do-it-yourself calendars and web pages. It supports both simplified and traditional Chinese characters.

ConfClerk is an application written in Qt, which makes conference schedules available offline. It displays the conference schedule from various views, support searches on various items (speaker, speech topic, location, etc.) and enables you to select favorite events and create your own schedule.

At the moment ConfClerk is able to import schedules in XML format created by the PentaBarf conference management system (or frab) used by e.g. FOSDEM, DebConf, FrOSCon, Grazer LinuxTage, and the CCC congresses.

ConfClerk is targeted at mobile devices but works on any system running Qt.

Remind allows you to remind yourself of upcoming events and appointments. Each reminder or alarm can consist of a message sent to standard output, or a program to be executed. It also features: sophisticated date calculation, moon phases, sunrise/sunset, Hebrew calendar, alarms, PostScript output and proper handling of holidays.

Hebcal is a program for converting between Hebrew and Gregorian dates, and generating lists of Jewish holidays for a given year. Shabbat, holiday candle lighting, and havdalah times are approximated using your location.

It can also show daily prayer times, the weekly Torah reading, and the daily leaf of Talmud. The program can help with counting of the Omer or with calculation of Hebrew yahrzeits, birthdays, or anniversaries.

adl-submit is a tool that can be used to submit events to any instance of the Agenda Du Libre (a web calendar originally meant for free software events). Users can set fields through the command line or create an XML that can be submitted with the adl-submit tool. While the Agenda Du Libre web application is available in multiple languages, most of the events on https://www.agendadulibre.org are in French and the adl-submit tool is only available in French.

Ccache is a compiler cache. It speeds up recompilation by caching previous compilations and detecting when the same compilation is being done again. Supported languages are C, C++, Objective-C and Objective-C++.

cdrecord converts a CD image in a ".bin / .cue" format (sometimes ".raw / .cue") to a set of .iso and .cdr tracks.

dvd+rw-tools, mostly known for its command growisofs, is a collection of DVD and Blu-ray Disc burning tools. It requires another program, such as mkisofs, genisoimage, or xorrisofs to create ISO 9660 images.

RipIT is used to extract audio from CDs.

libudfread is a C library for reading UDF file systems. UDF is a file system mostly used for DVDs and other optical media. It supports read-only media (DVD/CD-R) and rewritable media that wears out (DVD/CD-RW).

CDemu is a software suite designed to emulate an optical drive and disc (including CD-ROMs and DVD-ROMs).