What is the JUK file format?
A .juk file contains source code written in Juka, a free, open-source programming language built to run the same code across many platforms. The file is plain UTF-8 text, so it holds readable statements: function and class declarations, loops, conditionals, try/catch blocks, and output calls such as printLine("test" + 5);.
Juka is the successor to an earlier language called Juliar, which used the .jlr extension. The project is maintained by the JukaLang community and its source lives on GitHub and Codeberg. Under the hood, Juka programs are handled by JukaCompiler, a .NET component that uses Microsoft's Roslyn libraries to turn source into .NET intermediate code, or runs it directly through an interpreter. Most people who meet a .juk file are developers trying out the language or working from its repositories.
Security & safety
RISK: MEDIUMA .juk file is plain-text source code and cannot execute on its own by being opened in an editor. The risk is in running it: Juka code compiled or interpreted through the Juka runtime can perform any action the language allows, so treat files from untrusted sources like any other unreviewed script and read the code before running it.
Format details
in a nutshell- KDE JuK music manager - JuK is a KDE audio jukebox and music player. It manages libraries and playlists but does not use a .juk data file; the name is unrelated to the Juka language.
- JUKU BASIC - A BASIC-like language for the JUKU computer exists as a hobby project; unrelated to Juka and not the dominant meaning of the .juk extension.
Programs that open JUK files
Windows3 apps
Juka (juka CLI)
Open-source Download the Juka release binary, then run juka yourfile.juk in a terminal to execute the file, or launch juka alone for the interactive REPL. 
Visual Studio Code
Free Open the .juk file to read and edit the source as plain text with syntax highlighting from a generic language mode. 
macOS2 apps
Juka (juka CLI)
Open-source Install Juka and .NET, then run ./juka yourfile.juk from Terminal to compile and run the file. 
Linux3 apps
Juka (juka CLI)
Open-source Install the .NET runtime and Juka, then run ./juka yourfile.juk to execute the source, or ./juka for the REPL.
JukaCompiler (NuGet library)
Open-source Reference the library in a C# project and call new JukaCompiler.Compiler().JukaCompile(fileName, (isFile: true)); to compile a .juk file programmatically.
Any text editor (nano, vim, gedit)
Open-source Open the .juk file to inspect or edit the plain-text source.
Juka Jupyter kernel
Open-source Install the Juka kernel for Jupyter/JupyterLab to run Juka code cells and load .juk snippets in a notebook. Technical details
deep spec| Encoding | UTF-8 / ASCII plain text |
| Byte order | Not applicable (text) |
| Container | None (flat text file) |
| Typical size | Under 100 KB for a single source module |
| Structure | Human-readable Juka source code: function and class declarations, variable assignments, loops (for/while), conditionals, try/catch blocks, and calls such as printLine(). Statements terminate with a semicolon. |
| Integrity | None built in |
| Platforms | Windows, macOS, Linux, FreeBSD, Android |
| Initial Release Full | 2020 (evolved from the earlier Juliar language, .jlr) |
| Notes | Juka source is compiled by JukaCompiler, which uses the Microsoft.CodeAnalysis (Roslyn) libraries to emit .NET intermediate code, or run directly through the Juka interpreter/REPL. The compiler targets .NET 8 and is distributed on NuGet as JukaCompiler. |
| Language Paradigm | General-purpose, imperative with functions and classes |
| Runtime | .NET 8 (cross-platform) |
| Released | 2020 |
| Latest version | Rolling release (JukaCompiler 0.0.x on NuGet) |
| Specification | codeberg.org |
JUK conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about JUK files.
Frequently asked questions
What is a .juk file?
How do I open a .juk file?
juka yourfile.juk in a terminal.How do I run a .juk program?
./juka yourfile.juk. Running juka with no arguments opens an interactive REPL instead.Is Juka the same as Juliar?
.jlr extension; the project was renamed to Juka, and new source files use .juk.Is a .juk file safe to open?
Can I turn a .juk file into an app?
.exe or a .dll assembly, and there are Juka apps that wrap it for mobile platforms.
