Live Code File Format (.m)

Since R2025a

Starting in R2025a, the Live Editor supports a new plain text Live Code file format (.m) for live scripts as an alternative to the default binary Live Code file format (.mlx). The plain text format is based on the standard MATLAB® code file format (.m) and supports all Live Editor features, including output, formatted text, interactive controls, and tasks. Live scripts saved in this format open in the Live Editor and behave like other live scripts.

Live script with a .m file extension in the Live Editor. The live script contains formatted text, code, and output.

Benefits to Plain Text Live Code File Format (.m)

There are several benefits to saving live scripts using the new plain text Live Code file format:

  • Files open in external code editors — You can open live scripts saved using the plain text Live Code file format in any external text or code editor that supports plain text files.

  • Increased transparency — Files saved using the plain text file Live Code format do not trigger security concerns. One exception might be if the live script contains images and plots, which are saved as Base64 (ASCII-binary) strings in the plain text file.

  • Improved integration with source control — You can use external source control tools to compare and merge live scripts saved using the plain text file Live Code format.

Save Live Scripts as Plain Text

To save a live script using the plain text Live Code file format (.m):

  1. Go to the Live Editor tab, and in the File section, select Save > Save As.

  2. Enter a name for your live script. If you are saving an existing live script using the plain text Live Code file format, enter a different name than the original filename to avoid shadowing issues.

  3. Select MATLAB Live Code File (UTF-8) (*.m) as the Save as type.

  4. Click Save.

By default, live scripts saved using the plain text Live Code file format (.m) open in the Live Editor. To open the file as plain text in the Editor, right-click the file in the Files panel and select Open as Text.

Note

Editing a live script as plain text might prevent it from opening correctly in the Live Editor.

Change the Default Live Script File Format

By default, new live scripts are saved using the binary Live Code file format (.mlx). To make the plain text Live Code file format the default file format for live scripts, go to the Home tab, and in the Environment section, click Settings. Select MATLAB > Editor/Debugger, and in the Live script format section, select M as the Default live script file format.

Structure of Plain Text Live Code File

The Live Editor uses custom markup to save formatted text, generated output, interactive controls, and tasks as plain text. The Live Editor saves the custom markup in two places within the live script file:

  • Alongside the code as inline markup

  • At the bottom of the file in an appendix

For example, suppose that you have a live script, fahrenheitconverter.m, saved using the plain text Live Code file format. By default, when you open fahrenheitconverter.m, the file opens in the Live Editor. To open fahrenheitconverter.m as plain text in the Editor, right-click the file in the Files panel and select Open as Text.

Notice that in both the Live Editor and Editor, the line number for the first code line is 3. The reason is that in live scripts saved using the plain text Live Code file format, each line of text accounts for one or more code lines in the saved file. In addition, because lines of text are saved as code comments in the file, inserting text between statements that span multiple code lines is not supported.

Side-by-side comparison of a plain text Live Code file (.m) open in the Live Editor and in the Editor. In the Live Editor, the file appears with formatted text, code, and output. In the Editor, the file appears as plain text with code and commented markup.

Inline Markup

The Live Editor uses inline markup to save text items, such as formatted text, tables, equations, and hyperlinks. For example, this live script contains markup for a title line and a normal text line.

Live script saved using the plain text Live Code file format (.m) open as plain text in the Editor, with the inline markup for the title and first paragraph on lines 1 and 2

Appendix

The Live Editor uses an appendix at the end of the file to save larger amounts of data that cannot be saved inline and to save file information that is not linked to a specific line number. For example, this live script contains an appendix with markup that saves the current view of the live script, as well as the two outputs that the live script creates.

Live script saved using the plain text Live Code file format (.m) open as plain text in the Editor, with the appendix at the end of the file

Reference IDs

For features that require additional markup, the Live Editor uses inline markup with a reference ID to save basic feature information inline and link to additional markup in the appendix. When merging live scripts that contain differences in reference IDs, make sure that the inline reference ID and the reference ID in the appendix match in the merged result.

Live script saved using the plain text Live Code file format (.m) open as plain text in the Editor, with matching output reference IDs in the inline markup and the appendix

Markup Details

In live scripts saved using the plain text Live Code file format, the Live Editor saves custom markup as comments. In general, the Live Editor uses Markdown to save text items, such as formatted text, tables, images, and hyperlinks, and LaTeX commands to save equations.

This table provides more information about the custom markup used in the plain text Live Code file format (.m).

Markup TypeMarkup Syntax

Formatted text

Text is saved inline using the %[text] markup. Markup within the line specifies the formatting. 

%[text] This is basic text
%[text] # This is a title
%[text] ## This is a header
%[text] This is **bold**, *italic*, `monospace`, and <u>underlined</u>
%[text]{"align":"center"} This block of text is center aligned

Table of contents

Table of contents is saved inline using the %[text:tableOfContents] markup. 

%[text:tableOfContents]{"heading": "Table of Contents"}

Code example

Code examples are saved inline using the %[text] markup.

Plain code example:

%[text] ```
%[text] x = 1;
%[text] y = "hello";
%[text] ```

MATLAB code example:

%[text] ```matlabCodeExample
%[text] x = 1;
%[text] y = "hello";
%[text] ```

Table

Tables are saved inline using the %[text:table] markup.

%[text:table]
%[text] | abc | def |
%[text] | --- | --- |
%[text] | 123 | 456 |
%[text:table]
Image

Images are saved both inline and in the appendix.

Syntax inline:

%[text] this image: ![alt text](text:image:imageid)

Syntax in appendix:

%[text:image:imageid]
%   data: { ... }
%---

Hyperlink

Hyperlinks are saved inline using the %[text] markup.

%[text] web page: [MathWorks Website](https://mathworks.com)  
%[text] file: [Duck Duck Go](/path/to/file.txt)
Equation

Equations are saved as LaTeX commands inline using the %[text] markup.

%[text] $x = 4^2${"altText": "equation alt text"}
Output

Output is saved using the %[output] markup both inline and at the bottom of the file in the appendix.

Syntax inline:

%[output:outputid]

Syntax in appendix:

%[output:outputid]
%   data: { ... }
%---

Control

Controls are saved using the %[control] markup both inline and in the appendix. The {"position":[start,end]} markup defines the start position and end position of the control within the code line.

Syntax inline:

%[control:controltype:controlid]{"position":[14,16]}

Syntax in appendix:

%[control:controltype:controlid]
%   data: { ... }
%---

Live Editor task

Live Editor tasks are saved using the %[task] markup both inline next to each task code line and in the appendix.

Syntax inline:

%[task:taskid]

Syntax in appendix:

%[task:taskid]
%   data: { ... }
%---

Live script view

The current view of the live script is saved using the %[metadata] markup in the appendix.

%[metadata:view]
%   data: {"layout":"inline","rightPanelPercent":40}
%---

Source Control

When using external source control tools, you can compare and merge live scripts saved using the plain text Live Code file format (.m) directly from the tool. Live scripts saved using the binary Live Code file format (.mlx) can only be compared using the MATLAB Comparison Tool.

For example, in GitHub®, when you add a live script saved using the plain text Live Code file format to a repository, you can see the differences between each revision of the file.

Diff of two versions of a live script saved using the plain text Live Code file format (.m) in GitHub

Source Control Limitations and Workarounds

Some external source control tools have limitations around file size that might prevent the comparison of live scripts saved using the plain text Live Code file format:

  • GitLab® and GitHub throw an error and do not display the differences in a file if the file size is too big.

  • Perforce® tries to display the differences but might become unresponsive if the file size is too big. To avoid Perforce becoming unresponsive, you can try disabling the Show Inline Differences option.

For the best results, try using GitHub Desktop or Visual Studio Code. You also can reduce file size by disabling the saving of output to your files. To disable saving output, go to the Home tab, and in the Environment section, click Settings. Select MATLAB > Editor/Debugger > Saving and in the Output Save Options section, clear Save output to file. Alternatively, clear all output before submitting your files to source control.

For more information, see the documentation for your source control tool.

See Also

Topics