Nota

There are lots of commands you can use from the terminal for performing mathematical functions. There's expr, for example, which performs addition, division, and subtraction and compares two values, and there's bc for more complicated expressions where high precision is important. Many terminal emulators, including Bash, even include their own mathematical interpreters, letting you perform some simple sums without even summoning a command. All of these methods are functional, but they're not terribly exciting or fun to use. The same can't be said for Nota, a terminal calculator with "rich notation rendering." What this means in practice is that you get a character-based graphical representation of your calculation, whether it's a simple sum or a more complex expression.

Unlike many other tools, Nota's calculations are the product of an interactive session, and when you start the tool you're asked to enter the various inputs you wish to process. But the clever part is that it's not expecting just numbers, but commands that use its own simple language. You can create variables, for instance (a=1), and use them in later inputs. Inputs can be decimal, hex, binary, named identifiers, and hidden within parentheses. Each input is always evaluated, so you can see what's happening. This process lets you create a function exactly as you might remember it – or code it. The output is always visually appealing, such as putting 1 over 2 when the input is 1/2, or an ASCII radical sign when evaluating sqrt[1/2]. Combine this with the variables, and you can process complex input much like you would on a piece of paper, only with each step being evaluated and with beautifully rendered text output. This is what makes Nota so interesting, and our new default terminal-based mathematical tool.

Project Website

http://codes.kary.us/nota/nota

The only additional feature we'd like to see in Nota is the ability to process input from the command line, rather than from its interactive session.

Coder notes

Boost Note

We often include note taking applications in these pages, but we've seldom looked at a note taking application designed specifically for programmers. That's what Boost Note is, and it's unique in several ways that can help improve the development process and address the problems typical with managing large, complex tasks. Alongside the usual support for Markdown and a live preview, it has full LaTeX support. This is perfect for including equations alongside your notes and embedded within the same output document. LaTeX is still unparalleled when it comes to layout and makes up for many of Markdown's minimalist shortcomings, but it's not the only trick, either. Other features include tags to help with indexing, and a snippet system that works much like Gist's. All of this is packaged in a slick, quick, and cross-platform app.

There is a paid version, and there is the option to store your notes in the cloud – which may be a good choice when the accompanying mobile app is released, but both cloud storage and subscriptions are optional. The project is fully open source, and there's also the option to store your data locally. A great feature that's typical of many paid-for applications is a set of tutorials and templates. These show you how Markdown is used, how tasks can be produced and tracked, which keyboard shortcuts to use, and how to use the storage options. The templates include a framework for brainstorming, a bug fix, meeting notes, and a weekly planner; they're a great way to get started. Several light and dark themes are included, and you can edit the syntax highlighting colors for your chosen types of code. You can also export directly as either HTML or as the raw Markdown, so you can always get hold of your data, regardless of where it's stored.

Project Website

https://boostnote.io/

Alongside your Markdown notes, you can also include attachments and thanks to KaTeX, even LaTex-formatted equations.