Fortunately, you can use Zeal, an offline documentation browser, to store programming language and software documentation on your computer and access it quickly and effectively. Zeal uses document sets (docsets) provided by Dash. They include documentation for many programming and scripting languages and libraries, as well as various software such as Docker, Nginx, WordPress and ElasticSearch, to name a few. Here’s how to install, use and customize Zeal on Linux.
Installing Zeal
Zeal is available in the software repositories of many Linux distributions, so you should install it using your native package manager if possible. On Ubuntu, Linux Mint, and Debian: On Arch Linux: On Gentoo: On Fedora:
Using Zeal
You can launch Zeal from your application menu/launcher or from a command-line terminal by typing zeal.
Zeal does not include any documentation by default. To view the available docsets, go to “Tools -> Docsets” and open the “Available” tab.
Select the docsets you want to store and click on “Download.” Once fetched, document sets are displayed in the upper-left pane in a navigable hierarchical structure. When applicable, the lower-left pane displays shortcuts to the elements of the current document page.
You can search all docsets by entering a query or a specific docset with the syntax docset:query. For instance, to search for Python’s re.match function, you would enter python:re.match. Note: with the compound search syntax (that is docset:query), the docset part is case sensitive, and the query part is case insensitive.
Customizing Zeal
Fonts
You can configure Zeal’s appearance to your liking with fonts and font sizes. To do so, go to “Edit -> Preferences -> Content” and then select a default font family and specific fonts for each font family.
Dark Mode
Zeal also provides a dark mode (in “Edit -> Preferences -> Content”), though it is only applied to document contents and not to the surrounding graphical interface as you can see in the following screenshot.
User-Defined CSS
If you are going to be using Zeal on a regular basis, then it’s worth devoting some time to tweak it to your own taste. You can use a custom stylesheet for greater and finer control over the appearance of documents. Create a new CSS file using your text editor: Enter the desired CSS rule sets, for example: Go to the “Edit -> Preferences -> Content -> Custom CSS” file to select the newly created CSS file. After saving your settings, the changes will be visible immediately. The following screenshot shows Zeal after applying the above CSS.
Conclusion
Zeal is a great tool for programmers and system administrators who tend to access documentation frequently. Since it stores documents locally, it can save you time and allow you to better focus on the work at hand. Additionally, unlike Web documents, it supports user-defined stylesheets for fine control over document appearance.
