Open Source Software for Linux
Perkeep
Perkeep is a set of free and open-source formats, protocols, and software for modeling, storing, searching, sharing and synchronizing data in the post-PC era. Data may be files or objects, tweets or 5TB videos, and you can access it via a phone, browser or FUSE filesystem. Perkeep is openly and actively developed and anyone is free the contribute to the project.
wikidPad
wikidPad is a Wiki-like note taking application for storing your thoughts, ideas, todo lists, contacts, or anything else you can think of to write down. What makes wikidPad different from other notepad applications is the ease with which you can cross-link your information. Links in a wiki are created by typing in WikiWords. wikidPad allows you to get a better undestanding of your research and documentation and allow you to better explore and rediscover your knowledge.
Apache Cassandra
Apache Cassandra is a free and open-source, distributed, wide column store, NoSQL database management system. Apache Cassandra is designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure. The database has become the choice of many organizations that need scalability and high availability without compromising performance. Apache Cassandra also provides support for replicating across multiple datacenters, providing lower latency for end users of Cassandra-powered applications.
Joplin
Joplin is a free and open source note taking and to-do list application. Joplin can handle large number of notes organised into notebooks and allow you to write memorable notes using markdown. With Joplin your notes are searchable, can be copied, tagged and modified either from the applications directly or from your own text editor.
Apache HBase
With Apache HBase manager realtime read/write access to your Big Data. Apache HBase is an open-source, distributed, versioned, non-relational database modeled after Google's Bigtable: A Distributed Storage System for Structured Data. Just as Bigtable leverages the distributed data storage provided by the Google File System, Apache HBase provides Bigtable-like capabilities on top of Hadoop and HDFS.
SpeedCrunch
SpeedCrunch is a free and open-source high-precision scientific calculator. The application features a fast, keyboard-driven user interface that displays results as you type. SpeedCrunch comes with over 80 built-in mathematical functions, if that's not enough, you can define your own functions. A library of built-in formulas that allows to you to review and insert commonly used formulas is also included. SpeedCrunch can be downloaded for macOS, Linux and Windows, and is licensed under the GNU General Public License.
RethinkDB
RethinkDB is a scalable, open-source database designed for real-time applications. When your app polls your database for data, it becomes slow, unscalable, and cumbersome to maintain. RethinkDB solves this by providing a new database access model, where developers can instruct the database to continuously push updated query results to their applications, without polling.
JingOS
JingOS is a free and open-source Linux distro designed specifically for tablets. The operating system take design ideas from iOS and iPad and brings them to Linux eco-system. It comes several basic mobile Linux apps, including Calendar, Timer, Files, Media Player, and Calculator. Yet it is still a fully functional operating system that can run Linux-based desktop apps like VS Code, Libre Office, Kdenlive and more. Allowing users to be as productive as they would on a desktop computer.
pgAdmin
The software pgAdmin is the most popular free and open-source administration panel for PostgreSQL. With pgAdmin developers can manage their database and also use it as a tool that is part of the development process. The software is released under the PostgreSQL/Artistic licence and can be used on macOS, Linux, Unix and Windows to manage PostgreSQL 9.2 and above.
gedit
gedit is a free and open source IDE native to the GNOME desktop environment. With gedit you can work with a wide range of programming languages including C, C++, Java, JavaScript, HTML, XML, Python and Perl. The IDE automatically detect programming language and provide code color highlighting accordingly. It also include features like search and replace, spell checking, printing and support for most filte types.