visdiff

R2026b

Compare two files or folders

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Syntax

visdiff(filename1,filename2)
visdiff(filename1,filename2,type)
comparison = visdiff(___)

Description

visdiff(filename1,filename2) opens the Comparison Tool and displays the differences between the two files or folders. The Comparison Tool supports MATLAB® code files, ZIP files, MAT files, and various other MATLAB, Simulink®, and scientific data file formats. For a complete list, see Input Arguments.

Use visdiff to compare two Simulink models, identify changes, and merge differences. For more information, see Model Comparison (Simulink).

To close all currently opened Comparison Tools, at the MATLAB Command Window, run comparisons.closeAll. (since R2026b)

example

visdiff(filename1,filename2,type) compares two files using the specified comparison type. If you do not specify a type, visdiff uses the default comparison type for your selected files. You can use this syntax to compare files only.

example

comparison = visdiff(___) compares two files and returns a comparison object that contains the differences between the specified files. Use the comparison object to manipulate the comparison at the command line, for example by applying filters and publishing comparison reports, or to examine the comparison result directly at the MATLAB Command Window (since R2026b). This syntax does not open the Comparison Tool and does not require a display. It is particularly useful for automating the creation of comparison reports for continuous integration (CI) workflows. This syntax does not support all file types. Supported files include Simulink models, Simulink data dictionaries, requirement and link set files, plain text files, MATLAB scripts, MATLAB apps, MAT files, and text-based source code files.

example

Examples

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Open Live Script

This example shows how to compare two files using relative and full paths.

Compare the two files lengthofline.m and lengthofline2.m in the current folder.

visdiff("lengthofline.m","lengthofline2.m")

Compare the two MAT files gatlin.mat and gatlin2.mat using a fully qualified file name.

visdiff(fullfile(pwd,"supportingFiles","mymatFiles","gatlin.mat"), ...
fullfile(pwd,"supportingFiles","mymatFiles","gatlin2.mat"))
Open Live Script

Compare the two files lengthofline.m and lengthofline2.m as binary.

If you do not specify the comparison type, visdiff compares the two files using the default text comparison type. By changing to the binary comparison type you can examine differences such as end-of-line characters. 

visdiff("lengthofline.m","lengthofline2.m","binary")

When comparing certain file types, you can manipulate the comparison report at the command line by specifying an output argument. Supported files include Simulink models, Simulink data dictionaries, requirement and link set files, plain text files, MATLAB scripts, MATLAB apps, MAT files, and text-based source code files.

For example, compare two Simulink model files and return a comparison object.

comparison = visdiff(modelname1,modelname2);

You can disable all filters from the model comparison report.

filter(comparison,"unfiltered");

To publish a comparison report to a file, use publish on the comparison object. The default format of the published report is HTML. publish saves the file in the current folder as filename1_filename2.html.

file = publish(comparison);
web(file)

Create a PDF comparison report named myreport. Save the report to the comparisonresults folder.

file = publish(comparison,format="PDF",Name="myreport",OutputFolder="comparisonresults");
web(file)

Supported report formats are HTML, PDF, PDF/A, and DOCX.

Note

PDF/A comparison reports are not supported on Linux®.

For instructions on how you can use visdiff to generate reports in your continuous integration workflows, see Attach Model Comparison Report to GitHub Pull Requests (Simulink).

Since R2026b

This example shows you how to compare two text files and examine the result of the comparison at the MATLAB Command Window.

Compare two files lengthofline.m and lengthofline2.m and retrieve the comparison report result from the comparison object comp.

comp = visdiff("lengthofline.m","lengthofline2.m");
result = comp.Result
result = 
  TextDiffResult with properties:

       Matches: [6x5 table]
    HasChanges: 1

The comparison report result is a TextDiffResult object with these two properties:

  • Matches — Line-by-line comparison results, returned as a table.

    ColumnTypeDescription
    LeftLineNumberdoubleLine number in the left file. This value is NaN for inserted lines.
    LeftLinestringText content from the left file. This value is missing for inserted lines.
    RightLineNumberdoubleLine number in the right file. This value is NaN for deleted lines.
    RightLinestringText content from the right file. This value is missing for deleted lines.
    ChangeTypestring

    Type of change. This value is equal to:

    • "unchanged" — The item is identical on both sides.

    • "modified" — The item exists on both sides but is different.

    • "inserted" — The item exists on the right side only.

    • "deleted" — The item exists on the left side only.

  • HasChanges — Whether the two compared files are different, returned as a logical scalar.

Examine the line-by-line comparison results at the MATLAB Command Window.

result.Matches
    LeftLineNumber          LeftLine           RightLineNumber           RightLine           ChangeType 
    ______________    _____________________    _______________    _______________________    ___________

           1          "function y = foo(x)"           1           "function y = foo(x)"      "unchanged"
           2          "% A simple function"           2           "% A modified function"    "modified" 
         NaN                                          3           "y = x + 2;"               "inserted" 
           3          "y = x + 1;"                    4           "z = x * 3;"               "modified" 
           4          "end"                           5           "end"                      "unchanged"
           5          ""                              6           ""                         "unchanged"

Count the number of inserted lines.

numLinesInserted = sum(result.Matches.ChangeType == "inserted")

numLinesInserted =
     1

Count the number of deleted lines.

numLinesDeleted = sum(result.Matches.ChangeType == "deleted")

numLinesDeleted =
     0

Count the number of modified lines.

numLinesModified = sum(result.Matches.ChangeType == "modified")

numLinesModified =
     2

Since R2026b

This example shows you how to compare two folders and examine the result of the comparison at the MATLAB Command Window.

Compare two folders folder1 and folder2 and retrieve the comparison report result from the comparison object comp.

comp = visdiff("folder1","folder2");
result = comp.Result
result = 
  TreeDiffResult with properties:

       Matches: [5x4 table]
    HasChanges: 1

The comparison report result is a TreeDiffResult object with these two properties:

  • Matches — Line-by-line comparison results, returned as a table.

    ColumnTypeDescription
    LeftPathcellPath segments of the left item, as displayed in the Comparison Tool, returned as a cell of string array. This value is missing for inserted items.
    RightPathcellPath segments of the right item, as displayed in the Comparison Tool, returned as a cell of string array. This value is missing for deleted items.
    ChangeTypestring

    Type of change. This value is equal to:

    • "unchanged" — The item is identical on both sides.

    • "modified" — The item exists on both sides but is different.

    • "inserted" — The item exists on the right side only.

    • "deleted" — The item exists on the left side only.

    Detailsstruct

    Parameter-level differences for a single matched item. The field of this structure is ParameterDiffResults and contains ParameterDiffResults objects.

    This table shows the properties of the ParameterDiffResults object.

    ColumnTypeDescription
    LeftNamestringParameter name in the left item.
    LeftValuestringParameter value in the left item.
    RightNamestringParameter name in the right item.
    RightValuestringParameter value in the right item.
    ChangeType Type of change. This value is equal to "unchanged", "modified", "inserted", or "deleted".

  • HasChanges — Whether the two compared files are different, returned as a logical scalar.

Examine the line-by-line comparison results at the MATLAB Command Window.

result.Matches
            LeftPath                     RightPath            ChangeType      Details  
    _________________________    _________________________    ___________    __________

    {["sub"                ]}    {["sub"                ]}    "unchanged"    1x1 struct
    {["sub"    "nested.txt"]}    {["sub"    "nested.txt"]}    "modified"     1x1 struct
    {[                     ]}    {["added.txt"          ]}    "inserted"     1x1 struct
    {["changed.txt"        ]}    {["changed.txt"        ]}    "modified"     1x1 struct
    {["deleted.txt"        ]}    {[                     ]}    "deleted"      1x1 struct

Count the number of inserted items.

numItemsInserted = sum(result.Matches.ChangeType == "inserted")

numItemsInserted =
     1

Count the number of deleted items.

numItemsDeleted = sum(result.Matches.ChangeType == "deleted")

numItemsDeleted =
     1

Count the number of modified items.

numItemsModified = sum(result.Matches.ChangeType == "modified")

numItemsModified =
     2

Since R2026b

This example shows you how to compare two MAT files and examine the result of the comparison at the MATLAB Command Window.

Compare two MAT files mat1.mat and mat2.mat and retrieve the comparison report result from the comparison object comp. In this example, the mat1.mat file consists of a structure named x with a = 1, b = 2, and c = 3 fields. The mat2.mat file consists of a structure named x with a = 1, b = 99, c = 3, and d = 4 fields.

comp = visdiff("mat1.mat","mat2.mat");
result = comp.Result
result = 
  TreeDiffResult with properties:

       Matches: [3×4 table]
    HasChanges: 1

The comparison report result is a TreeDiffResult object with these two properties:

  • Matches — Line-by-line comparison results, returned as a table.

    ColumnTypeDescription
    LeftPathcellPath segments of the left item, as displayed in the Comparison Tool, returned as a cell of string array. This value is missing for inserted items.
    RightPathcellPath segments of the right item, as displayed in the Comparison Tool, returned as a cell of string array. This value is missing for deleted items.
    ChangeTypestring

    Type of change. This value is equal to:

    • "unchanged" — The item is identical on both sides.

    • "modified" — The item exists on both sides but is different.

    • "inserted" — The item exists on the right side only.

    • "deleted" — The item exists on the left side only.

    Detailsstruct

    Parameter-level or text-level differences for a single matched item. The fields of this structure are ParameterDiffResults and/or TextDiffResults. Each field contains ParameterDiffResults and TextDiffResults objects respectively.

    This table shows the properties of the ParameterDiffResults object.

    ColumnTypeDescription
    LeftNamestringParameter name in the left item.
    LeftValuestringParameter value in the left item.
    RightNamestringParameter name in the right item.
    RightValuestringParameter value in the right item.
    ChangeType Type of change. This value is equal to "unchanged", "modified", "inserted", or "deleted".

  • HasChanges — Whether the two compared files are different, returned as a logical scalar.

Examine the line-by-line comparison results at the MATLAB Command Window.

result.Matches
                     LeftPath                                     RightPath                     ChangeType     Details  
    __________________________________________    __________________________________________    __________    __________

    {["x  (1x1 struct)"                     ]}    {["x  (1x1 struct)"                     ]}    "modified"    1x1 struct
    {["x  (1x1 struct)"    "b  (1x1 double)"]}    {["x  (1x1 struct)"    "b  (1x1 double)"]}    "modified"    1x1 struct
    {[                                      ]}    {["x  (1x1 struct)"    "d  (1x1 double)"]}    "inserted"    1x1 struct

Check the parameter-level differences for the first item in the Matches table. The report shows that the field names of the x structure in the two MAT files are different, because the x structure in the mat2.mat file contains an additional d field.

result.Matches.Details(1).ParameterDiffResults.Matches

1×5 table

      LeftName       LeftValue      RightName       RightValue     ChangeType
    _____________    _________    _____________    ____________    __________

    "Field Names"    "a, b, c"    "Field Names"    "a, b, c, d"    "modified"

Count the number of top-level inserted variables. The x structure in the mat2.mat file has an additional d field.

matches = result.Matches;
isTopLevelVar = @isscalar;
numInsertedVars = sum(matches.ChangeType == "inserted" & cellfun(isTopLevelVar, matches.RightPath))
numInsertedVars =
     1

Count the number of top-level deleted variables.

numDeletedVars = sum(matches.ChangeType == "deleted" & cellfun(isTopLevelVar, matches.LeftPath))

numDeletedVars =
     0

Count the number of top-level modified variables.

numModifiedVars = sum(matches.ChangeType == "modified" & cellfun(isTopLevelVar, matches.LeftPath))
numModifiedVars =
     1

Since R2026b

This example shows you how to compare two Simulink models and examine the result of the comparison at the MATLAB Command Window.

Compare two Simulink models model_v1.slx and model_v2.slx and retrieve the comparison report result from the comparison object comp. 

comp = visdiff("model_v1.slx","model_v2.slx");
result = comp.Result
result = 
  ModelDiffResult with properties:

    FilterSummary: "Applied filters: Nonfunctional, Ports, Annotations"
          Matches: [7x6 table]
       HasChanges: 1

The comparison report result is a ModelDiffResult object with these three properties:

  • FilterSummary — Summary of the active filters at the time of the comparison. To change the active filters after you already performed a comparison, use the filter function of the comparison object comp and retrieve the comparison report result again.

    For example, to remove all currently active filters, run these commands:

    filter(comp, 'unfiltered');
result_unfiltered = comp.Result

  • Matches — Model element comparison results, returned as a table.

    ColumnTypeDescription
    LeftPathcellPath segments of the left item, as displayed in the Comparison Tool, returned as a cell of string array. This value is missing for inserted items.
    RightPathcellPath segments of the right item, as displayed in the Comparison Tool, returned as a cell of string array. This value is missing for deleted items.
    ChangeTypestring

    Type of change. This value is equal to:

    • "unchanged" — The item is identical on both sides.

    • "modified" — The item exists on both sides but is different.

    • "inserted" — The item exists on the right side only.

    • "deleted" — The item exists on the left side only.

    Detailsstruct

    Parameter-level or text-level differences for a single matched item. The fields of this structure are ParameterDiffResults and/or TextDiffResults. Each field contains ParameterDiffResults and TextDiffResults objects respectively.

    This table shows the properties of the ParameterDiffResults object.

    ColumnTypeDescription
    LeftNamestringParameter name in the left item.
    LeftValuestringParameter value in the left item.
    RightNamestringParameter name in the right item.
    RightValuestringParameter value in the right item.
    ChangeType Type of change. This value is equal to "unchanged", "modified", "inserted", or "deleted".

    LeftObjectcell

    Domain-specific object:

    • Simulink.comparisons.SimulinkObject — Elements that a Simulink handle can represent, including blocks, lines, ports, and annotations.

    • Stateflow® objects

    • missing — No object representation is available.

    RightObjectcell

  • HasChanges — Whether the two compared files are different, returned as a logical scalar.

Examine the model element comparison results at the MATLAB Command Window. In this example, this command examines a single modified block.

result.Matches(3,:)
        LeftPath                  RightPath           ChangeType     Details                 LeftObject                          RightObject
    ____________________    ____________________      __________    __________    ________________________________    ________________________________
    {["Simulink","Const1"]} {["Simulink","Const1"]}   "modified"    1x1 struct    {1x1 SimulinkObject (Constant …)}  {1x1 SimulinkObject (Constant …)}

The report states that a Constant block has been modified.

Check how the Constant block has been modified.

result.Matches.Details(3).ParameterDiffResults.Matches
    LeftName    LeftValue    RightName    RightValue    ChangeType
    ________    _________    _________    __________    __________

    "Value"        "5"        "Value"        "10"       "modified"

The report states that the value of the Constant block changed from 5 to 10.

Count the number of deleted blocks.

matches = result.Matches;
isBlock = @(obj) isprop(obj, "Handle") && get_param(obj.Handle, "Type") == "block";
numDeletedBlocks = sum(matches.ChangeType == "deleted" & cellfun(isBlock, matches.LeftObject))
numDeletedBlocks =
     0

Count the total number of modified parameters across all matched elements.

paramDiffResults = [matches.Details.ParameterDiffResults];
numModifiedParams = sum(vertcat(paramDiffResults.Matches).ChangeType == "modified")

numModifiedParams =
     2

If the model supports Stateflow operations, you can, for example, check the number of different states. Count the number of inserted states.

isState = @(obj) isa(obj, "Stateflow.State")
numInsertedStates = sum(matches.ChangeType == "inserted" & cellfun(isState, matches.RightObject))
numInsertedStates =
     1

Input Arguments

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File or folder name, specified as a character vector or string. filename can include a relative path to the current folder or a full path.

This table shows the supported file types.

File TypeFile Extension
MATLAB
MATLAB code file.m
MATLAB live code file.mlx, .m (since R2025a)
Plain textAny
Text-based source code.c, .cpp, .java, etc.
MATLAB App.mlapp
BinaryAny
Folder-
ZIP file.zip
MATLAB figure.fig
MAT file.mat
Project definition files.xml
Project archive.mlproj
Dependency GraphML.graphml
Simulink
Simulink models.slx, .mdl
Simulink model template.sltx
Simulink project template.sltx
Simulink data dictionary.sldd
Other Products
Requirements Toolbox™.slreqx. For more information, see Create and Save Printable Reports of Comparison Results (Requirements Toolbox).
Requirements Toolbox links.slmx. For more information, see Create and Save Printable Reports of Comparison Results (Requirements Toolbox).
Simulink Test™.mldatx
SimBiology® models.sbproj
System Composer® models.slx
Simscape® files.ssc
Scientific Data (since R2026a)
HDF5 file.h5, .hdf5
NetCDF file.nc
SOFA file.sofa

You can also use the Comparison Tool for basic comparisons for many other file extensions including .prj, .req, .cvf, .wrl, .x3s, .ssc, .xml, and .tlc.

Note

For HDF5, netCDF, and SOFA files, the Comparison Tool displays the differences in the schemas of the files. The schema comparison includes the hierarchical structure of the data as well as attributes and metadata, but it does not include the actual data stored in the files.

You can use the Comparison Tool to compare HDF5 files, netCDF-4 files, SOFA files, and Version 7.3 MAT files to each other. When you compare a Version 7.3 MAT file to an HDF5, netCDF-4, or SOFA file, only the schemas of the files are compared. (since R2026a)

Comparison type, specified as "text" or "binary". Some comparisons do not support all of the comparison types. If you specify a comparison type that is not supported, MATLAB displays an error.

To examine differences such as end-of-line characters in text files, specify the "binary" comparison type.

Output Arguments

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Comparison object for manipulating the comparison at the command line, for example, by applying filters and publishing comparison reports, or for examining the comparison report at the MATLAB Command Window. Supported files include Simulink models, plain text files, MATLAB scripts, MATLAB apps, and text-based source code files.

Alternative Functionality

You can open the Comparison Tool interactively.

  • MATLAB editors — Open a file in the MATLAB Editor or in the Live Editor. In the Editor or Live Editor toolstrip, select Compare > Compare To. Then, select the file you want to compare to.

    You can also compare a file with the autosave version or the saved version on disk. In the Editor tab, select Compare > Compare to Version on Disk or Compare to Backup. If your file is modified, the Editor saves the file before comparing. The Compare to Version on Disk and Compare to Backup options are only available if the option for automatically saving changes to a file is disabled. To disable the option, go to the Home tab, and in the Environment section, click Settings. Then, select Editor/Debugger and clear Save changes upon clicking away from a file. This option is not available in the Live Editor.

  • Simulink Editor — To compare a model that is open in the Simulink Editor to another model on disk, on the Modeling tab, in the Evaluate & Manage section, click Compare To.

  • Files or Project panel — To compare two files on disk, select both files. Then, right-click and select Compare Selected Files/Folders. The Comparison Tool opens the file you select first on the left.

Version History

Introduced in R2008b

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See Also

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