5 file types use the .r file extension.

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What is an R file?

An R file is a script written in R, a programming language used for statistical analysis and graphing purposes. It contains code that can be executed within the R software environment. R files may include commands that create objects (functions, values, etc.) and produce visualizations of the computed data.

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Category: Developer Files

Rez Source Code File

An R file may also be a source code file used by Rez, an older resource compiler once included with Apple's developer tools. It contains written definitions of application resources, such as strings, icons, menus, alerts, and other structured data. Each R file includes both the resource types and the individual resource entries that Rez uses to build a resource fork for a classic Mac application.

Developers wrote R files to organize and manage the resources used by applications built for classic Mac OS and early versions of macOS. Rez processed these text declarations and produced compiled resource data that could be embedded in application bundles or other files.

The companion tool DeRez could reverse this process by converting compiled resources back into readable R files. Although modern versions of Apple Xcode no longer include these tools, they were once a standard part of older Mac development workflows.

You can open R files with any text editor, such as Apple TextEdit , Sublime Text , or Microsoft Visual Studio Code . Older versions of Apple Xcode included the Rez compiler, which developers used to compile R files into application resources.

Programs that open or reference R files

Updated: November 21, 2025

Right Audio Channel File

An R file may also be an audio file that stores the right channel of a stereo recording. It is typically created when audio production software exports each stereo channel as a separate file, allowing engineers to edit or process the left and right channels independently. Because the file contains only one side of a stereo mix, it must be combined with a matching .L (left channel) file to form the complete audio track.

Audio editing and digital audio workstation ( DAW ) applications create R files when users choose to work with split stereo audio rather than a single interleaved file. For example, Digital Performer, Cubase, and other multitrack editors may generate R files during export or when users record audio in a format that separates channels. This workflow can be useful for sound engineers who need separate control over each channel for mixing, effects processing, or correction.

NOTE: R files are usually saved in standard audio formats, such as .WAV or .AIFF . The extension .r indicates their channel role rather than their container format.

You can open R files with most DAWs, audio editors, and media players, including Avid Pro Tools , Audacity , and VideoLAN VLC Media Player (as long as the app supports the format in which the R file is saved). The apps will recognize it as a mono audio track. For full stereo playback, you must load both the R and corresponding L files and pair them within the audio software.

Programs that open R files

Updated: November 20, 2025

Ratfor Source Code

An R file may also be a source code file used by Rational Fortran (Ratfor), a preprocessor for the FORTRAN programming language. It contains a mix of standard FORTRAN code and Ratfor-specific statements, which provide a more modern and flexible syntax . Before compilation , Ratfor converts the file into standard FORTRAN code that a FORTRAN compiler can process.

Developers use Ratfor to write code using constructs that FORTRAN does not natively support, such as C-style control flow statements, including if-else , switch , while , and for loops. This functionality makes it easier to write, read, and maintain complex programs while still generating valid FORTRAN code for execution. Developers working on scientific, engineering, or numerical computing projects often used Ratfor to simplify coding in older FORTRAN environments.

You can open R files with any plain text editor, such as Microsoft Notepad , Notepad++ , or Microsoft Visual Studio Code , to view or edit the source code. To compile and run the code, you first process it with a Ratfor preprocessor to generate standard FORTRAN source code, which a FORTRAN compiler, such as gfortran or Intel Fortran Compiler, can then compile.

Programs that open or reference R files

Updated: November 20, 2025

REBOL Script

Script written in the REBOL programming language; contains code that can be compiled into an executable program; may be a program file or a header file referenced by other REBOL program files.

REBOL stands for "Relative Expression Based Object Language." The language is commonly used for creating Internet scripts and applications.

Programs that open or reference R files

Updated: January 9, 2010